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Influence of Acetylene on Growth of Sulfate-Respiring Bacteria

Payne, W. J.; Grant, M. A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1982 Português
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87.88014%
At a concentration of 20% of the atmosphere of the culture flasks, acetylene inhibited growth and carbon dioxide production by Desulfovibrio desulfuricans and Desulfovibrio gigas. The bacteria did not reduce acetylene to ethylene, and neither acetylene dicarboxylic acid nor ethylene was inhibitory. At 10%, acetylene was partially inhibitory for the desulfovibrios. At 5%, acetylene impeded the rate but did not limit the extent of growth and catabolism of the desulfovibrios. Desulfotomaculum ruminis was affected only negligibly, if at all, by acetylene and ethylene at any of these concentrations.

Influence of Plant Phenolic Acids on Growth and Cellulolytic Activity of Rumen Bacteria

Chesson, Andrew; Stewart, Colin S.; Wallace, R. John
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1982 Português
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97.8947%
Isolated rumen bacteria were examined for growth and, where appropriate, for their ability to degrade cellulose in the presence of the hydroxycinnamic acids trans-p-coumaric acid and trans-ferulic acid and the hydroxybenzoic acids vanillic acid and 4-hydroxybenzoic acid. Ferulic and p-coumaric acids proved to be the most toxic of the acids examined and suppressed the growth of the cellulolytic strains Ruminococcus albus, Ruminococcus flavefaciens, and Bacteroides succinogenes when included in a simple sugars medium at concentrations of >5 mM. The extent of cellulose digestion by R. flavefaciens and B. succinogenes but not R. albus was also substantially reduced. Examination of rumen fluid from sheep maintained on dried grass containing 0.51% phenolic acids showed the presence of phloretic acid (0.1 mM) and 3-methoxyphloretic acid (trace) produced by hydrogenation of the 2-propenoic side chain of p-coumaric and ferulic acids, respectively. The parent acids were found in trace amounts only, although they represented the major phenolic acids ingested. Phloretic and 3-methoxyphloretic acids proved to be considerably less toxic than their parent acids. All of the cellulolytic strains (and Streptococcus bovis) showed at least a limited ability to hydrogenate hydroxycinnamic acids...

Exopolysaccharide Distribution of and Bioemulsifier Production by Acinetobacter calcoaceticus BD4 and BD413

Kaplan, Nachum; Rosenberg, Eugene
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1982 Português
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87.88615%
The heavily encapsulated Acinetobacter calcoaceticus BD4 and the “miniencapsulated” single-step mutant A. calcoaceticus BD413 produced extracellular polysaccharides in addition to the capsular material. The molar ratio of rhamnose to glucose (3:1) in the extracellular BD413 polysaccharide fraction was similar to the composition of the capsular material. In both strains, the increase in capsular polysaccharide was parallel to cell growth and remained constant in stationary phase. The extracellular polysaccharides were detected starting from mid-logarithmic phase and continued to accumulate in the growth medium for 5 to 8 h after the onset of stationary phase. Strain BD413 produced one-fourth the total rhamnose exopolysaccharide per cell that strain BD4 did. Depending on the growth medium, 32 to 63% of the rhamnose polysaccharide produced by strain BD413 was extracellular, whereas in strain BD4 only 7 to 14% was extracellular. In all cases, strain BD413 produced more extracellular rhamnose polysaccharide than strain BD4 did. In glucose medium, strain BD413 also produced approximately 10 times more extracellular emulsifying activity than strain BD4 did. The isolated capsular polysaccharide obtained after shearing of BD4 cells showed no emulsifying activity. Thus...

Growth Kinetics and Yield Coefficients of the Extreme Thermophile Thermothrix thiopara in Continuous Culture

Brannan, Daniel K.; Caldwell, Douglas E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1983 Português
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78.267725%
Thermothrix thiopara did not appear to be stressed at high temperature (72°C). Both the actual and theoretical yields were higher than those of analogous mesophilic sulfur bacteria, and the specific growth rate (μmax) was more rapid than that of most autotrophs. The specific growth rate (0.58 h−1), specific maintenance rate (0.11 h−1), actual molar growth yield at μmax (Ymax = 16 g mol−1), and theoretical molar growth yield (YG = 24 g mol−1) were all higher for T. thiopara (72°C) than for mesophilic (25 to 30°C) Thiobacillus spp. The growth efficiencies for T. thiopara at 70 and 75°C (0.84 and 0.78) were significantly higher than at 65°C (0.47). Corresponding specific maintenance rates were highest at 65°C (0.41 h−1) and lowest at 70 and 75°C (0.11 and 0.15 h−1, respectively). Growth efficiencies of metabolically similar mesophiles were generally higher than for T. thiopara. However, the actual yields at μmax were higher for T. thiopara because its theoretical yield was higher. Thus, at 70°C, T. thiopara was capable of deriving more metabolically useful energy from thiosulfate than were mesophilic sulfur bacteria at 25 and 30°C. The low growth efficiency of T. thiopara reflected higher maintenance expenditures. T. thiopara had higher maintenance rates than Thiobacillus ferroxidans or Thiobacillus denitrificans...

Isolation and Characterization of an H2-Oxidizing Thermophilic Methanogen

Ferguson, Thomas J.; Mah, Robert A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1983 Português
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87.97244%
A thermophilic methanogen was isolated from enrichment cultures originally inoculated with sludge from an anaerobic kelp digester (55°C). This isolate exhibited a temperature optimum of 55 to 60°C and a maximum near 70°C. Growth occurred throughout the pH range of 5.5 to 9.0, with optimal growth near pH 7.2. Although 4% salt was present in the isolation medium, salt was not required for optimal growth. The thermophile utilized formate or H2-CO2 but not acetate, methanol, or methylamines for growth and methanogenesis. Growth in complex medium was very rapid, and a minimum doubling time of 1.8 h was recorded in media supplemented with rumen fluid. Growth in defined media required the addition of acetate and an unknown factor(s) from digester supernatant, rumen fluid, or Trypticase. Cells in liquid culture were oval to coccoid, 0.7 to 1.8 μm in diameter, often occurring in pairs. The cells were easily lysed upon exposure to oxygen or 0.08 mg of sodium dodecyl sulfate per ml. The isolate was sensitive to tetracycline and chloramphenicol but not penicillin G or cycloserine. The DNA base composition was 59.69 mol% guanine plus cytosine.

Growth and Sporulation of Entrapped Bacillus subtilis Cells

Baudet, Catherine; Barbotin, Jean-Noël; Guespin-Michel, Janine
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1983 Português
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97.81161%
Growing Bacillus subtilis cells were immobilized in k-carrageenan gel beads. Growth and sporulation of entrapped cells were studied by two different methods: cell enumeration and transmission electron microscopy. Immobilized growing cells had a shorter generation time than free cells did, whereas sporulation timing was unchanged. When steady state was reached, cell density was very high in gel beads.

Prototheca zopfii Krüger Strain UMK-13 Growth on Acetate or n-Alkanes

Koenig, David W.; Ward, H. B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1983 Português
Relevância na Pesquisa
87.95842%
A new strain of Prototheca zopfii Krüger was grown on acetate or on pure n-alkanes. A maximum acetate-supported exponential growth of 12 divisions day−1 occurred at pH 5 and 30°C. At 25°C, growth on n-alkanes was almost as fast, but no growth occurred at 30°C. After 4 days at 25°C, 34 to 45% of the n-alkanes had been removed, whereas at 21°C and slower growth, utilization was twofold greater after 15 days. Rates of growth and utilization increased markedly after a point of sudden emulsification.

Betaine: New Oxidant in the Stickland Reaction and Methanogenesis from Betaine and l-Alanine by a Clostridium sporogenes-Methanosarcina barkeri Coculture

Naumann, Evelyn; Hippe, Hans; Gottschalk, Gerhard
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1983 Português
Relevância na Pesquisa
87.73955%
Growing and nongrowing cells of Clostridium sporogenes fermented betaine with l-alanine, l-valine, l-leucine, and l-isoleucine as electron donors in a coupled oxidation-reduction reaction (Stickland reaction). For the substrate combinations betaine and l-alanine and betaine and l-valine balance studies were performed; the results were in agreement with the following fermentation equation: 1 R- CH(NH2)-COOH + 2 betaine + 2 H2O → 1 R-COOH + 1 CO2 + 1 NH3 + 2 trimethylamine + 2 acetate. Growth and production of trimethylamine were strictly dependent on the presence of selenite in the medium. With cell suspensions it was shown that C. sporogenes was unable to catabolize betaine as a single substrate. Betaine, however, was reduced to trimethylamine and acetate under an atmosphere of molecular hydrogen. For the reduction of betaine by cell extracts of C. sporogenes, dimercaptans such as 1,4-dithiothreitol could serve as electron donors. No betaine reductase activity was detected in cells grown in a complex medium without betaine. The pH optimum of betaine reductase was at pH 7.3. When C. sporogenes was cocultured with Methanosarcina barkeri strain Fusaro on betaine together with l-alanine, an almost complete conversion of the two substrates to CH4...

Effect of Sugar Concentration in Jerusalem Artichoke Extract on Kluyveromyces marxianus Growth and Ethanol Production

Margaritis, Argyrios; Bajpai, Pratima
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1983 Português
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97.86036%
The effect of inulin sugars concentration on the growth and ethanol production by Kluyveromyces marxianus UCD (FST) 55-82 was studied. A maximum ethanol concentration of 102 g/liter was obtained from 250 g of sugars per liter initial concentration. The maximum specific growth rate varied from 0.44 h−1 at 50 g of sugar per liter to 0.13 h−1 at 300 g of sugar per liter, whereas the ethanol yield remained almost constant at 0.45 g of ethanol per g of sugars utilized.

Selection of Wine Yeasts for Growth and Fermentation in the Presence of Ethanol and Sucrose

Benítez, Tahía; del Castillo, Lucas; Aguilera, Andrés; Conde, Jaime; Cerdáolmedo, E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1983 Português
Relevância na Pesquisa
97.89378%
To optimize the conversion of carbohydrates to ethanol, strains of several Saccharomyces species were examined for the ability to grow and ferment in a range of sucrose and ethanol concentrations. A total of 632 wine yeasts, most of them isolated from wineries in Andalusia and Extremadura, southwestern Spain, were subjected to screening and selection. Growth and fermentative capacity in different ethanol and sucrose concentrations varied from one strain to another. There was no correlation between growth and fermentative capacity. The best 35 strains grew in 15% ethanol and fermented in 18% ethanol. Ethanol accumulated, although at a reduced rate, after the cells stopped growing. Most yeast strains were highly fermentative in 50% sucrose. Some of them effectively utilized the carbohydrates of the culture, yielding final ethanol concentrations of > 14%. Of the 35 selected strains, 16 were promising for genetic analysis and breeding because of their capacity to sporulate. These strains were homothallic, and their spores were viable. The meiotic products analyzed so far were also homothallic.

Growth and Methanogenesis by Methanosarcina Strain 227 on Acetate and Methanol

Smith, Michael R.; Mah, Robert A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1978 Português
Relevância na Pesquisa
98.1997%
Methanosarcina strain 227 exhibited exponential growth on sodium acetate in the absence of added H2. Under these conditions, rates of methanogenesis were limited by concentrations of acetate below 0.05 M. One mole of methane was formed per mole of acetate consumed. Additional evidence from radioactive labeling studies indicated that sufficient energy for growth was obtained by the decarboxylation of acetate. Diauxic growth and sequential methanogenesis from methanol followed by acetate occurred in the presence of mixtures of methanol and acetate. Detailed studies showed that methanol-grown cells did not metabolize acetate in the presence of methanol, although acetate-grown cells did metabolize methanol and acetate simultaneously before shifting to methanol. Acetate catabolism appeared to be regulated in response to the presence of better metabolizable substrates such as methanol or H2-CO2 by a mechanism resembling catabolite repression. Inhibition of methanogenesis from acetate by 2-bromoethanesulfonate, an analog of coenzyme M, was reversed by addition of coenzyme M. Labeling studies also showed that methanol may lie on the acetate pathway. These results suggested that methanogenesis from acetate, methanol, and H2-CO2 may have some steps in common...

Growth and Polysaccharide Production by Methylocystis parvus OBBP on Methanol

Hou, C. T.; Laskin, A. I.; Patel, R. N.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1979 Português
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87.95104%
Methylocystis parvus OBBP, an obligate methylotroph originally isolated as a methane-utilizing bacterium, was cultivated on methanol as a sole source of carbon. After adaptation to high methanol levels, this organism grew on methanol with a maximum specific growth rate of 0.65 h−1. The pH optimum for growth was between 7 and 9, and the temperature optimum was between 30 and 37°C. Methanol concentrations higher than 5% (by weight) were toxic. Formaldehyde, at a concentration greater than 1 mM, inhibited growth. Formate was neither a substrate nor an inhibitor. An extracellular viscous heteropolysaccharide was produced during growth. The maximum production of the total biomass was 14.5 g (dry weight) per liter of broth. The dried biomass contained 22% (wt/wt) crude protein and 62% (wt/wt) polysaccharide. The main components of the polysaccharide were d-glucose (82%) and l-rhamnose (14%).

Bile Salt 3α- and 12α-Hydroxysteroid Dehydrogenases from Eubacterium lentum and Related Organisms

Macdonald, Ian A.; Jellett, Joanne F.; Mahony, David E.; Holdeman, Lillian V.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1979 Português
Relevância na Pesquisa
87.84202%
Thirty-two strains of Eubacterium lentum and phenotypically similar anaerobic gram-positive bacilli were screened for intracellular bile salt 3α- and 12α-hydroxysteroid dehydrogenase (HSDHase) activities. These organisms were categorized into four groups: (A) those containing 12α-HSDHase only (10 strains), (B) those containing 3α- and 12α-HSDHase (13 strains), (C) those containing 3α-HSDHase only (2 strains), and (D) those devoid of any measurable HSDHase activity (7 strains). Of the respective four groups, 9/10, 13/13, 0/2, and 0/7 were like the neotype strain of E. lentum (ATCC 25559) in that they produced H2S in a triple sugar iron agar butt, reduced nitrate to nitrite, and weakly decomposed hydrogen peroxide. The other strains were variable for nitrate reduction and activity on hydrogen peroxide, but all the organisms in the first three categories (with one exception) were H2S producers (triple sugar iron agar butt) and all (with one exception) were designated E. lentum, whereas the organisms of category B were non-H2S producers (triple sugar iron agar butt). Five of these seven were not stimulated by arginine and are designated “phenotypically similar organisms.” Thin-layer chromatography of extracted spent bacterial medium of four representative strains from each group grown in the presence of cholate revealed the presence of (A) 12-oxo product...

Na+, K+, and Nonspecific Solute Requirements for Induction and Function of Galactose Active Transport in an Antarctic Psychrophilic Marine Bacterium †

Hayasaka, Steven S.; Morita, Richard Y.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1979 Português
Relevância na Pesquisa
87.95104%
An Antarctic psychrophilic marine Vibrio sp., with the inducible ability to accumulate non-metabolizable [14C]methyl-β-d-thiogalactoside through a galactose transport system, was isolated. Induction of [14C]methyl-β-d-thiogalactoside uptake was found to have a specific Na+ requirement which was higher than that required for maximal uptake and growth. A specific K+ requirement was found to be quantitatively the same for uptake, growth, and induction. At low suboptimal growth salinities in artificial seawater, growth, uptake, and induction were inhibited more by the generally low solute concentration than by a specific ion deficiency. Evidence was given that the effect of the nonspecific solute was not completely osmotic in nature. The nonspecific solute requirement was greatest for induction, followed by growth and substrate uptake.

Formation of Short-Chain Fatty Acids from H2 and CO2 by a Mixed Culture of Bacteria

Goldberg, I.; Cooney, C. L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1981 Português
Relevância na Pesquisa
87.88351%
The biological utilization of CO2 and H2 for the formation of short-chain fatty acids was studied by using a mixed culture of bacteria. Optimization of a medium was carried out in continuous culture to identify limiting factors which controlled growth and production of organic acids. The optimal pH for growth and acid production was 7.0 at 37°C; the maximal cell concentration obtained was 5.9 g of cells per liter (dry weight), and the maximal amount of volatile acids formed was 4.7 g/liter, with acetic acid as the predominant acid. With the optimized medium, it was found that the rate of transfer of hydrogen or carbon dioxide, or both, from gas to liquid was the limiting factor which controlled growth and production of acids.

Carbohydrate Fermentation by Streptococcus cremoris and Streptococcus lactis Growing in Agar Gels

Thomas, Terence D.; Turner, Keith W.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1981 Português
Relevância na Pesquisa
88.08086%
When lactic streptococci were embedded in agar gels and incubated at 30°C, the end products of carbohydrate fermentation depended on the initial cell density, which determined the subsequent distribution and size of colonies in the gel. With high initial cell densities, microcolonies formed close together and lactose and glucose were converted almost entirely to lactate. However, inoculation with a small number of cells, which then grew to form widely spaced and comparatively large colonies, resulted in up to 30% diversion of end product, usually to formate, ethanol, and acetate. In these “low-colony-density” gel cultures, the initial rate of fermentation was exponential and only lactate was formed. However, this rate then became linear and fermentation became progressively more heterolactic. Streptococcus lactis ML8 was the only strain among the 10 tested which remained homolactic. Incubation at temperatures either above or below the optimum for growth and metabolism decreased the diversion to end products other than lactate. The change from homo- to heterolactic fermentation appears to be caused by carbohydrate depletion in the vicinity of the colony, so that fermentation is then limited by the diffusion of substrate. Growth of cells on gel surfaces exposed to air resulted in up to 40% diversion of end product from lactate...

Comparison of Growth and Toxin Production in Two Vaccine Strains of Bacillus anthracis

Johnson, Anna D.; Spero, Leonard
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1981 Português
Relevância na Pesquisa
87.80249%
Two vaccine strains of Bacillus anthracis were monitored in a 10-liter fermentor to compare growth patterns and toxin production. Under identical conditions, the Sterne strain produced all three components of anthrax toxin, whereas strain V770 produced only the protective antigen.

Solvent Production and Morphological Changes in Clostridium acetobutylicum

Jones, D. T.; van der Westhuizen, A.; Long, S.; Allcock, E. R.; Reid, S. J.; Woods, D. R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1982 Português
Relevância na Pesquisa
87.99584%
The morphological and cytological changes which occurred in Clostridium acetobutylicum P262 during the production of acetone, butanol, and ethanol in an industrial fermentation medium were identified and correlated with the growth and physiological changes. The swollen, cigar-shaped clostridial forms were involved in the conversion of acids to neutral solvents, and there was a correlation between the number of clostridial forms and the production of solvents. Sporulation mutants which were unable to form clostridial stages (cls mutants) did not produce solvents. Oligosporogenous mutants which showed reduced clostridial stage formation produced intermediate levels of solvents. Sporulation mutants blocked after the clostridial stage, which were unable to form mature spores (spo mutants), produced normal levels of solvents.

Thermothrix thiopara: Growth and Metabolism of a Newly Isolated Thermophile Capable of Oxidizing Sulfur and Sulfur Compounds

Brannan, Daniel K.; Caldwell, Douglas E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1980 Português
Relevância na Pesquisa
88.27552%
Thermothrix thiopara is isolated from hot sulfur springs. It occurs in situ at a temperature of 72°C, a pH of 7.0, and an HS- concentration of 17.4 μmol/liter (0.8 ppm). The organism was capable of autotrophic growth. Sulfite, sulfur, and polythionates were formed and subsequently degraded to sulfate during growth with thiosulfate as the sole energy source. Thiosulfate was oxidized by the polythionate pathway, and the stoichiometry of growth on thiosulfate was determined. The organism was also capable of heterotrophic growth in amino acids and simple sugars. A source of reduced sulfur (methionine, glutathione) was required for heterotrophic growth. Growth occurred aerobically or anaerobically with nitrate as a terminal oxidant. Both nitrous oxide and dinitrogen were produced. At 73°C the maximum autotrophic growth rate in batch culture using thiosulfate was 0.56 generation per h. Under the same conditions in continuous culture, washout occurred at a dilution rate of 0.3 to 0.4 per h, corresponding to a cellular growth rate of 0.43 to 0.58 generation per h. This was nearly three times the growth rate for Thiobacillus denitrificans. T. thiopara is gram negative. It was also found to be both lysozyme and penicillin susceptible. As a result...

Isolation of a Strain of Clostridium thermoaceticum Capable of Growth and Acetic Acid Production at pH 4.5

Schwartz, Robert D.; Keller, Frederick A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1982 Português
Relevância na Pesquisa
87.73635%
Using a series of pH controlled batch fermentations operated in a fed-batch mode and adaptation and selection techniques where pH and acetic acid provided the selective pressures, we isolated a culture of Clostridium thermoaceticum that can grow and produce acetic acid at pH 4.5. At pH 4.5 the fastest mass doubling time was 36 h, and the highest acetic acid concentration reached was 4.5 g/liter. Generally, as the pH was decreased from 6.0 and the initial acetic acid concentration increased, the mass doubling time increased, and the final acetic acid concentration decreased. These observations can be explained in terms of inhibition by the free acetic acid concentration at a given pH, relative to the total acetic acid concentration (free acid plus acetate ion). We have thus reached one of the criteria determined by us to be required for an economically viable fermentation acetic acid process, i.e., pH 4.5. A second requirement for a mass doubling time of about 7 h (0.1/h dilution rate) can probably be reached by selection in continuous culture. The final requirement for an acetic acid concentration of 50 g/liter will be the most difficult to achieve in view of the organism's sensitivity to low concentrations of free acetic acid.