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  • Biochemistry and Biotechnology  (10)
  • Inorganic Chemistry  (2)
  • Wiley-Blackwell  (12)
  • American Institute of Physics
  • 1
    Electronic Resource
    Electronic Resource
    Zur Carbonylierung von Zirconocenhydrid-Komplexen (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 2447-2460 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Carbonylation of Zirconocene Hydride ComplexesThe reaction of η2-acylzirconocene complexes 1 with oligomeric zirconocene hydrides (Cp2ZrH2)x (3) or (Cp2ZrClH)x (4) yields binuclear μ-aldehyde-zirconocene hydride complexes 2. The molecular geometry of an example of this type of compound, the μ-acetaldehyde-zirconocene dihydride 2c, in the crystalline state was determined by X-ray analysis. A degenerate „dyotropic“ rearrangement of substrates 2c and e proceeding fast in solution can be detected by dynamic 1H NMR spectroscopy. Reaction of the dinuclear dihydride 2e with carbon monoxide eventually yields the enediolate complex 15-cis. The mechanism of this process of a reductive coupling of two CO molecules by substrate 2e can be traced by several established intermediates. The isolated (η2-formaldehyde)zirconocene complex 11 appears to have a key function in this transformation of carbon monoxide.
    Notes: Die Reaktion der η2-Acylzirconocen-Komplexe 1 mit den oligomeren Zirconocenhydriden (Cp2ZrH2)x (3) oder (Cp2ZrClH)x (4) führt zu zweikernigen μ-Aldehyd-zirconocenhydrid-Komplexen 2. Die molekulare Geometrie eines Beispiels dieser Verbindungsklasse, des μ-Acetaldehydzirconocendihydrids 2c, im Kristall wurde durch eine Röntgen-Strukturanalyse bestimmt. Eine in Lösung rasch verlaufende degenerierte „dyotrope“ Umlagerung der Substrate 2c und e kann durch dynamische 1H-NMR-Spektroskopie erkannt werden. Die Umsetzung des zweikernigen Dihydrids 2e mit Kohlenmonoxid führt schließlich zum Endiolatkomplex 15-cis. Der Mechanismus dieser reduktiven Kupplung zweier CO-Moleküle am Substrat 2e wird durch die nachgewiesenen Zwischenprodukte abgesteckt. Dem isolierten (η2-Formaldehyd)zirconocen-Komplex 11 kommt eine Schlüsselrolle bei dieser Umwandlung des Kohlenmonoxids zu.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821150707
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  • 2
    Electronic Resource
    Electronic Resource
    Reaktionsverhalten und Struktur von (s-cis-1,3-Dien)-zirconocen-Komplexen (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 3311-3323 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactivity and Structure of (s-cis-1,3-Diene)zirconocene ComplexesFor (s-cis-η4-diene)zirconocene complexes 1 the rates of thermal automerization as well as the reaction with carbon monoxide exhibit a comparable and pronounced dependence on substituents of the diene ligand. Based on X-ray structures of the complexes with 2,3-dimethyl-(1d) and 2,3-diphenylbutadiene (1f), this substituent effect is interpreted as arising from a different σ-bonding character of these ligands. Hydrolysis of the carbonylation products obtained from 1 yields cyclopentenones.
    Notes: Bei (s-cis-η4-Dien)zirconocen-Komplexen 1 zeigen die Geschwindigkeiten der thermischen Automerisierung wie auch der Reaktion mit Kohlenmonoxid eine ähnliche und ausgeprägte Abhängigkeit von den Substituenten am Dienliganden. An Hand der Röntgenstrukturanalysen der Komplexe mit 2,3-Dimethyl-(1d) und 2,3-Diphenylbutadien (1f) wird dieser Substituenteneinfluß mit dem unterschiedlichen σ-Bindungscharakter dieser Liganden erklärt. Die Hydrolyse der Carbonylierungsprodukte von 1 liefert Cyclopentenone.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821151009
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  • 3
    Electronic Resource
    Electronic Resource
    Enzyme loading in a solid support with nonuniform pore size distribution (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 35 (1990), S. 976-982 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The concept of pore size distribution is incorporated into the Clark model of enzyme immobilization in the present study. This refined model predicted that in the case of small harmonic pore radius with the same surface area and porosity of the support, more enzyme could be loaded in a support with nonuniform pores than that with uniform pores. In comparing the enzyme loading efficiency of the support with two different pore size distributions, the one with Gaussian distribution had the greater amount of enzyme immobilized than the other one with Rajagopalan's distribution. Furthermore, more enzyme could be loaded in a support with wider Gaussian pore size distribution than that with narrower distribution. The immobilized enzyme profile in the solid support with pore size distribution displayed a stepwise pattern which differed appreciably from the sigmoidal profile predicted for the support with uniform pore size. This stepwise enzyme distribution profile became sigmoidal with decreasing hT or increasing k. The new model could be used for designing protocols for an enzyme immobilization process.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260351004
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  • 4
    Electronic Resource
    Electronic Resource
    A method using solubility to predict dry matter digestibility of cellulosic materials (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 19 (1977), S. 143-152 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A rapid chemical procedure based on the solubility of a holocellulose sample in a system of dimethyl sulfoxide with paraformaldehyde has been developed to provide a laboratory method for predicting dry matter digestibility of cellulose containing samples. The amount of dry matter solubilized by the chemical procedure was closely correlated with anaerobic, in vitro, rumen fluid digestion and with digestibility as measured by aerobic Cellulomonas, sp. bacteria. The quantity of solvent and dissolving time had little effect on solubility over a wide range. The method is rapid, well suited for various cellulosic materials, and may be carried out with simple equipment and facilities.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260190111
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  • 5
    Electronic Resource
    Electronic Resource
    Preparation and performance of immobilized yeast cells in columns containing no inert carrier (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 25 (1983), S. 363-375 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Schizosaccharomyces pombe was cultivated in a medium of glucose (10 g/L) malt extract (3 g/L), yeast extract (3 g/L), and bactopeptone (5 g/L) to form flocs. More than 95% of the cell population were flocculated. Variation in glucose concentration (from 10 to 100 g/L) did not affect flocculation. Yeast extract helped induce flocculation. Application of the immobilized yeast for the continuous production of ethanol was tested in a column reactor. Soft yeast flocs (50-200 mesh) underwent morphological changes to heavy particles (0.1-0.3 cm diameter) after continuously being fed with fresh substrates in the column. Productivity as high as 87 g EtOH L-1 h-1 was obtained when a 150 g/L glucose medium was fed. The performance of this yeast reactor was stable over a two-month period. The ethanol yield was 97% of the theoretical maximum based upon glucose consumed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260250206
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  • 6
    Electronic Resource
    Electronic Resource
    Kinetics of enzymatic hydrolysis of olive oil in biphasic organic-aqueous systems (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 38 (1991), S. 761-766 
    Details
    ISSN: 0006-3592
    Keywords: biphasic system ; lipase-catalyzed hydrolysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A theoretical model for the lipase-catalyzed hydrolysis of high-concentration olive in biphasic isooctane-aqueous systems has been proposed and confirmed by experiments. The enzymatic reaction of the Michaelis-Menten type that occurred at the interface between organic and aqueous phases was assumed in deriving the rate equations, from which the maximum reaction rate could be obtained by carefully adjusting the volume ratio between the two phases to the optimal value. Equilibrium conversions higher than 98% for 0.1 g/L olive oil in isooctane were attained for systems with volume ratios up to one. Fractions of lipase and lipase-substrate complex adsorbed at the interface increased and seemed to approach to asymptotic values asthe rotation speed of impeller increased. Activity of the lipase showed no apparent change between 26 and 37°C, but decrease rapidly with temperature above 43°C. The methodology presented in this work might be used to find kinetic parameters for reactor design and scaleup.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260380710
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  • 7
    Electronic Resource
    Electronic Resource
    Kinetics, mechanism, and time course analysis of lipase-catalyzed hydrolysis of high concentration olive oil in AOT-isooctane reversed micelles (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 38 (1991), S. 206-211 
    Details
    ISSN: 0006-3592
    Keywords: reversed micelles ; lipase ; hydrolysis ; competitive product inhibition ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Candida rugosa lipase has been used to investigate the hydrolysis of high concentration olive oil in the AOT-isooctane reversed micellar system at Wo = 10, pH 7.1, and 37°C. Results from this work show the hydrolytic reaction obeys Michaelis-Menten kinetics up to the initial substrate concentration of 1.37M, with turnover number kcat and Michaelis constant KM of 67.1 μmol/min mg enzyme and 0.717M, respectively. A competitive inhibition by the main product, oleic acid, has been found with a dissociation constant KI for the complex EP* of 0.089M. The rate equation was further analyzed in the time course reaction and was found in agreement with the experimental results for lower substrate concentrations, up to 0.341M. Large deviation occurred at high substrate concentrations, which may be due to the effects of large consumption of water on kinetics, on the formation of glycerol, and on the deactivation of lipase in the hydrolysis reaction as well.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260380213
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  • 8
    Electronic Resource
    Electronic Resource
    Alginate-chitosan coacervation in production of artificial seeds (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 42 (1993), S. 449-454 
    Details
    ISSN: 0006-3592
    Keywords: artificial seed ; sodium alginate ; chitosan ; complex coacervation ; encapsulation ; embryoid viability ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Survival of secondary embryoids of winter oilseed rape (Brassica napus ssp. oleifera cv. Primor) has been used as an assay for the development of artificial seeds involving complex coacervation of alginate (polyanion) with chitosan (polycation). Germination frequency of 100% was achieved for encapsulated embryoids when alginate formed the inner matrix and chitosan the outer layer. When the matrix makeup was reversed, there was no germination of embryoids. The artificial seeds produced were hardened in dilute alkaline solutions of NaOH and Ca(OH)2. An optimum setting time could be selected based on a quantitative measurement of resistance of hardened capsules to compression and the germination frequency of the encapsulated embryoids. © 1993 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260420407
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  • 9
    Electronic Resource
    Electronic Resource
    Action of lipolytical enzymes in biphasic organic-aqueous systems: Dynamics of the irreversible Michaelis-Menten reaction (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 41 (1993), S. 603-611 
    Details
    ISSN: 0006-3592
    Keywords: dynamics of lipolytic enzymes ; modal analysis ; biphasic systems ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Through simple model analysis, the mass action kinetic model for lipolytic enzymes in biphasic aqueous-organic systems can be simplified using the quasi-steady state assumption (or the quasi-equilibrium state assumption) for the adsorbed enzyme E* or the enzyme-substrate complex E*S. Some parameter combinations leading to the above assumptions are derived confirmed by full numerical integration of the whole enzymatic process. The results may be classified into three categories: (1) the quasi-equilibrium state assumption for E*, (2) the quasi-steady state assumption for E*, and (3) the quasi-steady state assumption for E*S. Further simplification for both E* and E*S is also discussed. © 1993 Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260410602
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  • 10
    Electronic Resource
    Electronic Resource
    High frequency production of embryos from liquid flask cultures of oilseed rape (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 54 (1997), S. 231-238 
    Details
    ISSN: 0006-3592
    Keywords: Brassica napus ssp. oleifera ; cell suspension ; somatic embryogenesis ; artificial seed ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: As part of the program to scale-up the production of artificial seeds of winter oilseed rape, Brassica napus ssp. oleifera, we established a liquid flask culture system that enables the high frequency production of freely suspended embryos. As many as 4000 embryos could be obtained from 1 mL packed-cell-volume of cells. For initiation of liquid flask cultures, four different types of callus tissues were used. Among them, the most embryogenic cell suspension cultures were obtained from spontaneous callus developed on the surface of secondary embryos precultured in medium supplemented with 2,4-dichlorophenoxyacetic acid (4.52 μM) and kinetin (0.46 μM) (type B callus). Growth curves of the cell suspension were determined and the cell suspension was able to grow in medium without plant growth regulators. Embryos were observed to developed directly from the cells without going through an obvious callus phase. When subcultured to agar medium containing 44.38 μM benzylaminopurine, about 43% of the embryos developed into plants. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54: 231-238, 1997
    Additional Material: 8 Ill.
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