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  • 1
    Publication Date: 2006-04-21
    Keywords: ddc: 610
    Language: English
    Type: conferenceObject
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Trends in Biotechnology 3 (1985), S. 257-261 
    ISSN: 0167-7799
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Four clostridial species (C. pasteurianum, C. butylicum, C. butyricum and C. tetanomorphum) grow on pyruvate. Two other species (C. roseum and C. rubrum) only ferment this compound; this is probably due to their inability to synthesize hexose phosphates from pyruvate (fructose-1,6-diphosphatase and pyruvate carboxylase are absent). The fermentation of pyruvate by the above clostridia yields acetate, carbon dioxide, hydrogen and small amounts of compounds more reduced than acetate. Hydrogen pressure increases the amount of ethanol, butanol and butyrate formed during the fermentation of pyruvate. Since C. roseum and C. rubrum contain a ferredoxin: NADP reductase it seems likely that NADPH2 is the coenzyme involved in ethanol formation. In accordance with this acetaldehyde and alcohol dehydrogenases exhibit activity with NADPH2. The glyceraldehyde-3-phosphate dehydrogenase of the clostridia under investigation is NAD specific and so is the β-hydroxy-butyryl-CoA dehydrogenase with the exception of C. kluyveri. The specific activity of hydrogenase and the coenzyme specificity of NAD(P) reductase vary among the clostridial species.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 92 (1973), S. 365-368 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A new strain of Desulfovibrio gigas was isolated from sludge of a sewage plant. The medium contained ethanol, sulfate, minerals, some vitamins but no source of combined nitrogen. Several enrichment cultures of sulfate reducers could be obtained by employing the method to sludge samples from various sewage plants. With respect to their morphology, the dominating bacteria were of the Desulfovibrio gigas type.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary After elucidating the composition of an anaerobic bacterial enrichment culture treating sulphite evaporator condensate (SEC), an effluent in the pulp and paper industry, we built up stepwise a defined mixed culture to convert the organic constituents of SEC (acetate, methanol, furfural) to methane and CO2. In batch cultures Desulfovibrio furfuralis and Methanobacterium bryantii degraded furfural in the absence of sulphate via inter-species H2 transfer yielding 0.42 mol methane and 1.87 mol acetate/mol furfural degraded. When Methanosarcina barkeri was added to this diculture, acetate was also transformed to methane yielding 0.93 mol methane/mol acetate converted. This consortium (D. furfuralis, Methanobacterium bryantii and Methanosarcina barkeri) degraded furfural in continuous culture (fixed-bed loop reactor) to 92%, but the conversion of acetate was only 67%. The conversion of acetate could be further improved to 86% by adding 10 mm sulphate to the medium. This resulted in a space time yield of 10.9 g chemical oxygen demand (COD)/1 per day for the overall conversion. With a consortium consisting of M. barkeri, Methanobrevibacter arboriphilus, Methanosaeta concilii and D. furfuralis, a synthetic SEC could be degraded at a space time yield of 13.35 g COD/1 per day. This defined culture degraded all the constituents of SEC at an efficiency of almost 90% compared to an enrichment culture under identical conditions.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The formation of acetic acid by the thermophilic nonsporeforming homoacetogenic bacterium Acetogenium kivui was studied under various conditions. In pH-controlled batch fermentation at pH 6.4 this bacterium was able to produce up to 625 mM of acetic acid from glucose within 50–60 h. The value of μ max obtained was about 0.17 h-1, the yield was about 2.55 mol of acetic acid per mol of glucose utilized. In continuous fermentation both substrate concentration and dilution rate (D) influenced the yield of acetate and the stationary concentration: a glucose concentration of 67 mM at D=0.09 h-1 resulted in 2.82 mol acetate/mol glucose and 190 mM acetate at a production rate of 17.1 mM/1 h. When the dilution rate was increased the production rate reached a maximal value of 43.2 mM/1 h at D=0.32 h-1. At a glucose concentration of 195 mM the dependence of yield upon dilution rate followed a similar pattern and an acetate concentration of 420 mM could be obtained. Enzymatic studies indicate that in A. kivui pyruvate ferredoxin-oxidoreductase and acetate kinase are inhibited at acetate concentrations higher than 800 mM. Based on these results a fed-batch fermentation was developed, which allowed to produce more than 700 mM acetic acid within 40–50 h.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 120 (1979), S. 181-183 
    ISSN: 1432-072X
    Keywords: Acetobacterium woodii ; Murein structure ; Cell wall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The isolated cell walls of Acetobacterium woodii contain a murein of the crosslinkage type B. d-Orinithinyl residues function as interpeptide bridges between the γ-carboxyl group of d-glutamic acid and the carboxyl group of the terminal d-analyl residue of an adjacent peptide subunit. The usual l-alanyl residue in position 1 of the peptide subunit is replaced by a l-seryl residue. As yet this murein type was only found in Eubacterium limosum, an organism which was supposed to be related to Acetobacterium because of some metabolic similarities.
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  • 8
    ISSN: 1432-072X
    Keywords: Zymomonas ; Glucose catabolism ; Ethanol inhibition ; 31P NMR in vivo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ethanol inhibition of glucose catabolism in Zymomonas mobilis was investigated using 31P NMR spectroscopy in vivo and of perchloric acid extracts from cell suspensions incubated with 0, 5 and 10% (w/v) ethanol. In vivo 31P NMR experiments revealed slower glucose utilization and decreased levels of nucleoside triphosphates in the presence of 10% ethanol as compared to controls. Using 31P NMR spectroscopy of perchloric acid extracts, intracellular accumulation of 3.4 mM 3-phosphoglycerate was found when 10% ethanol was present in the medium. No accumulation of this metabolite occurred in cells incubated with 0 and 5% ethanol. Enzyme assays confirmed that phosphoglycerate-mutase and enolase were inhibited 31 and 40%, respectively, in the presence of 10% ethanol in the test system. Therefore, under the conditions used the decrease in the fermentative activity of Z. mobilis at high ethanol concentrations is due to inhibition of phosphoglycerate-mutase and enolase.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 65 (1969), S. 318-328 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary On the basis of the known fermentation balance and of the enzyme activities reported in Clostridium kluyveri the ethanol-acetate fermentation of Clostridium kluyveri has been analyzed with respect to possible ATP-yielding reactions and to the significance of the evolution of hydrogen gas during the fermentation. The fermentation pathway presented allows the following conclusions: hydrogen gas is an essential end product of the ethanol-acetate fermentation. For each two moles of hydrogen gas evolved one mole of acetyl coenzyme A becomes available to the cells for ATP synthesis, and it is not necessary to assume that ATP is synthesized by Clostridium kluyveri by electron transport phosphorylation. Hydrogen gas must be formed in the dehydrogenation of acetaldehyde. Since Clostridium kluyveri contains a NAD reductase, less than one mole of hydrogen gas is formed per mole of acetaldehyde oxidized, thus explaining that acetate is required for the fermentation of ethanol. It could be demonstrated that growth of Clostridium kluyveri is slow in a hydrogen atmosphere as compared with growth in an argon atmosphere. The general fermentation equation constructed is in accordance with the experimental data of Bornstein and Barker and of Thauer et al.
    Notes: Zusammenfassung Auf der Grundlage bekannter Gärungsanalysen und der in zellfreien Extrakten nachgewiesenen Enzymaktivitäten wurde die Äthanol-Acetat-Gärung von Clostridium kluyveri auf mögliche Energie liefernde Reaktionen hin untersucht. Das entworfene Schema der Äthanol-Acetat-Gärung erlaubt folgende Schlußfolgerungen: Die Bildung von molekularem Wasserstoff während der Gärung its von elementarer Bedeutung für den Energiestoffwechsel von C. kluyveri. Je Mol freigesetzten Wasserstoffs stehen C. kluyveri 0,5 Mole Acetyl-Coenzym A für die Energiegewinnung zur Verfügung, und es ist überflüssig, eine ATP-Synthese durch Elektronentransport-Phosphorylierung anzunehmen. Der molekulare Wasserstoff muß bei der Dehydrogenierung des Acetaldehyds gebildet werden. Da hierbei weniger als ein Mol molekularer Wasserstoff je Mol Acetaldehyd entsteht und ein Teil des Wasserstoffs auf NAD übertragen wird, ist Acetat als Wasserstoffacceptor für die Vergärung des Äthanols notwendig. Die abgeleitete Gärungsgleichung stimmt mit den von Bornstein und Barker und von Thauer et al. ermittelten Gärungsbilanzen überein. Es konnte nachgewiesen werden, daß C. kluyveri in einer Wasserstoffatmosphäre sehr viel langsamer wächst als in einer Argonatmosphäre.
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  • 10
    ISSN: 1432-072X
    Keywords: Acetobacterium woodii ; Hydrogen-oxidizing acetate-forming anaerobe ; Fine structure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acetobacterium woodii is a Gram-positive anaerobic nonsporeforming bacterium able to grow on H2 and CO2 as sole sources of energy. The product of fermentation is acetic acid. Fine structural analysis showed rod-shaped flagellated cells, and coccoid cells without flagella arranged predominantly in pairs and chains. The cell wall was found to be composed of three layers. The cell surface exhibited a periodic array of particles consisting of subunits. The cytoplasmic membrane showed particles either either in random distribution or in a hexagonal pattern. Intracytoplasmic membranes were rarely observed, whereas inclusion bodies of varying shapes, predominantly in an uncommon disc-shape, could frequently be observed. Their content was dissolved in ultrathin sections indicating hydrophobic nature.
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