Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-072X
    Keywords: Phenol fermentation Reductive dehydroxylation Hydrogen partial pressure Ring cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Fermentative degradation of phenol was studied using a non-methanogenic, pasteurised enrichment culture containing two morphologically different bacteria. Phenol was fermented to benzoate, acetate and butyrate and their relative occurrence depended on the concentration of hydrogen. Proportionately more benzoate was formed with high initial levels of H2. The influence of PH2 on the fermentation pattern was studied both in dense cell suspensions and in growing cultures by addition of hydrogen. An increase in growth yield (OD578) was observed, compared to controls, as a consequence of phenol degradation; however, the increase was less in H2-amended treatments, in which most of the phenol ended up as benzoate. The degradation of phenol in the dense cell suspension experiments was dependent on CO2. Benzoate was not degraded when added as a substrate to the growing culture. This is, to our knowledge, the first report concerning the fermentative degradation of phenol to non-aromatic products.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-072X
    Keywords: Key words     Mesophilic acetate oxidation ; Methanogenesis ; Ammonium ; Syntrophy ; Interspecies hydrogen transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract      In a mesophilic (37°C) triculture at a high ammonium concentration and pH 8, methanogenesis from acetate occurred via syntrophic acetate oxidation. Studies with 14C-labelled substrates showed that the amount of labelled methane formed from 1-14C-labelled acetate was equal to that formed from 2-14C-labelled acetate. Labelled methane was also formed from H14CO3 –. These results clearly showed that both the methyl and carboxyl groups of acetate were oxidized to CO2, and that CO2 was reduced to CH4 through hydrogenotrophic methanogenesis. During growth of the triculture, a significant isotopic exchange between the carboxyl group of acetate and bicarbonate occurred. As a result, there was a decrease in the specific activity of 1-14C-acetate, and the production of 14CO2 was slightly higher from 1-14C- than from 2-14C-acetate. For each mole acetate degraded, 0.94 mol methane was formed; 9.2 mmol acetate was metabolized during the 294 days of incubation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-072X
    Keywords: Pleomorphic ; Clostridium sp. nov. ; Saccharolytic ; Glucose uptake ; Swelling cells ; Morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new species of sporulating saccharolytic anaerobe, designated as Clostridium quinii sp. nov., is described. A gram-positive strain BS1, was isolated from the granular metanogenic sludge (UASB) from a waste-water treatment plant at a sugar refinery. The strain exhibits a series of morphological stages, developing from a spore to a small rod to a motile rod (peritrichous flagella) in the exponential growth phase, and then swelling to form cigar-shaped cells, exhibiting tumbling movements, in the late exponential growth phase before finally becoming large nonmotile ovoid cells in the stationary phase. Swelling occurs as a result of glucose being taken up and stored as a glycogen-like substance. The main fermentation products when growing on glucose is H2, CO2, formate, acetate and ethanol as well as small amounts of butyrate during exponential growth. Lactate is formed during the stationary phase, when glucose is abundant. Optimal conditions for growth is 40–45°C and pH of around 7.4. The type strain BS1 contains 28.0% mol G+C.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-072X
    Keywords: Mesophilic acetate oxidation ; Methanogenesis ; Ammonium ; Syntrophy ; Interspecies hydrogen transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a mesophilic (37°C) triculture at a high ammonium concentration and pH8, methanogenesis from acetate occurred via syntrophic acetate oxidation. Studies with 14C-labelled substrates showed that the amount of labelled methane formed from 1-14C-labelled acetate was equal to that formed from 2-14C-labelled acetate. Labelled methane was also formed from H14CO3 -. These results clearly showed that both the methyl and carboxyl groups of acetate were oxidized to CO2 and that CO2 was reduced to CH4 through hydrogenotrophic methanogenesis. During growth of the triculture, a significant isotopic exchange between the carboxyl group of acetate and bicarbonate occurred. As a result, there was a decrease in the specific activity of 1-14C-acetate, and the production of 14CO2 was slightly higher from 1-14C- than from 2-14C-acetate. For each mole acetate degraded, 0.94 mol methane was formed; 9.2 mmol acetate was metabolized during the 294 days of incubation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1574-6941
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract: Concentrations of two phospholipid fatty acids (PLFAs) specific for methane-oxidizing bacteria (16:1 ω8 and 18:1 ω8), were used to estimate the biomass and cell numbers of this group of bacteria in two Sphagnum-dominated boreal peatlands. Concentration ranges of 16:1 ω8 and 18:1 ω8 were 0.0–73 and 1.0–486 pmol g−1 of wet peat, respectively. Concentrations in the peat of each fatty acid were positively correlated with the potential methane oxidation activity (Vmax), which was used as an independent estimate of methanotrophic biomass. This correlation suggests that the two PLFAs are good biomarkers for the population of methanotrophic bacteria in peatlands. Concentrations of the two PLFAs were transformed to cell numbers using conversion factors for the cell content of PLFAs, average cell volume and percentage of cellular dry matter. The total cell number of methanotrophic bacteria in peat samples from a range of sites and depths ranged between 0.3 and 51 × 106 cells g−1 of wet peat, with similar proportions of type I and type II methanotrophic bacteria in most samples. Within particular peat profiles, numbers of methanotrophic bacteria were highest around the level of the water table, implying that the supplies of methane and oxygen largely determine the biomass distribution of methanotrophic bacteria in this type of peatlands.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 154 (1997), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The metabolism of the syntrophically acetate-oxidizing Clostridium ultunense was investigated with cell extracts of the pure culture and the methanogenic triculture from which C. ultunense was isolated. Enzyme measurements indicated that: (1) the CO dehydrogenase (Wood) pathway was used both during acetate formation and during acetate oxidation; (2) methylene-tetrahydrofolate reductase activity was not detected during acetate oxidation; (3) two different methylene-tetrahydrofolate dehydrogenase enzymes were active, depending on the direction in which the Wood pathway was used. The hydrogen partial pressure in the headspace of a growing triculture varied between 1.6 and 6.8 Pa, indicating that C. ultunense and the methanogenic partner each get about −17 kJ per mol reaction in this syntrophic cooperation, thus operating at the lowermost range of energy to be exploited by a living organism.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    PO Box 1354, 9600 Garsington Road , Oxford OX4 2XG , UK . : Blackwell Science Ltd
    Geophysical prospecting 53 (2005), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: In a sedimentary environment, layered models are often capable of representing the actual geology more accurately than smooth minimum structure models. Furthermore, interval thicknesses and resistivities are often the parameters to which non-geophysicist experts can relate and base decisions on when using them in waste site remediation, groundwater modelling and physical planning.We present a laterally constrained inversion scheme for continuous resistivity data based on a layered earth model (1D). All 1D data sets and models are inverted as one system, producing layered sections with lateral smooth transitions. The models are regularized through laterally equal constraints that tie interface depths and resistivities of adjacent layers. Prior information, e.g. originating from electric logs, migrates through the lateral constraints to the adjacent models, making resolution of equivalences possible to some extent. Information from areas with well-resolved parameters will migrate through the constraints in a similar way to help resolve the poorly constrained parameters. The estimated model is complemented by a full sensitivity analysis of the model parameters, supporting quantitative evaluation of the inversion result.Examples from synthetic 2D models show that the model recognition of a sublayered 2D wedge model is improved using the laterally constrained inversion approach when compared with a section of combined 1D models and when compared with a 2D minimum structure inversion. Case histories with data from two different continuous DC systems support the conclusions drawn from the synthetic example.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 4 (1997), S. 256-258 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Measurements on the current-voltage-magnetic field characteristics of a space-charge-limited cylindrical cross-field diode below cutoff are presented. The measured current is found to be lower than predicted by simple cold-fluid theory. This reduction combined with observed oscillations in the current can be explained by secondary electron emission from the anode, leading to an increase of space charge in the diode. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Nuclear Instruments and Methods in Physics Research Section A: 320 (1992), S. 183-200 
    ISSN: 0168-9002
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...