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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 32 (1986), S. 1088-1098 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A restricted diffusion model is developed to study the immobilization of enzyme in porous solid supports. Simulation studies have been carried out for various combinations of process variables and parameters of the immobilization system. The model has also been used to develop a method for estimating the intrinsic rate constant of immobilization when enzyme diffusion into the support is restricted. Results of experiments in which glucose oxidase was immobilized in porous glass supports are consistent with model simulations.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 39 (1992), S. 679-687 
    ISSN: 0006-3592
    Keywords: immobilized enzyme distribution ; diffusion cell ; active-site titration ; controlled-pore glass ; cell profile ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The total and active immobilized enzyme (IME) distributions in porous supports are studied both theoretically and experimentally. In order to determine experimentally the enzyme distribution profiles within a single particle, we construct a diffusion cell containing controlled-pore glass particles such that the cell would mimic a large pellet support. Our purpose is to study the interplay between the diffusion process within the interparticle void space and immobilization process in the controlled-pore glass particles onto the evolution of the (total and active) enzyme distributions. A mathematical model is developed to describe the interaction of various processes within the diffusion cell. The immobilized enzymes are determined for a system of trypsin and controlled-pore glass particles. The total amount of enzymes are determined by the amino acid analysis, and the active fraction is obtained by an active-site titration. The experimentally measured total IME profiles compare very well with that predicted by the model. The determined active enzyme profile is found to be nonuniform one, and it represents about 40% of the total enzyme immobilized in the support particles.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 40 (1992), S. 743-747 
    ISSN: 0006-3592
    Keywords: immobilized enzyme ; active enzyme ; diffusion ; controlled-pore glass ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The method Presented earlier by Hossain and Do determine the active enzyme distribution and relevant rate parameters under the condition of strong diffusional resistance is extended in this article to cover the cases of comparable diffusion and reaction rates (3 〈 φ 〈 20). The theory proposed herein is tested wtih the experimental data of hydrogen perioxide-catalase immobilized on controlled-pore glass (CPG) particles of small size (150 μm). © 1992 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1126-1135 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article deals with the mathematical modeling of the process of enzyme immobilization in porous membranes. During the initial period, an analytical solution is available to extract the rate constant for immobilization. Beyond this period, the model equations are solved numerically to yield the transient response of the enzyme concentration in the immobilizing solution and also the evolution of the enzyme loading profile inside the membrane. It is found that the immobilization practically ceases even through the attachment sites are still available within the membrane.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 29 (1987), S. 545-551 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new method is presented to determine (1) the rate constant for the main reaction, (2) the rate constant for deactivation, (3) the effective diffusivity, and (4) the active enzyme distribution within a porous solid support by utilizing data of bulk substrate concentration versus time in a continuous stirred basket reactor. The method relies on an assumption of parallel deactivation mechanism with strong pore diffusional resistance with respect to substrate species. The data of hydrogen peroxide-immobilized catalase published in the literature are used to demonstrate the theory. A parameter determination procedure is also presented.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 31 (1988), S. 730-736 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experiments have been carried out for immobilizing enzyme-catalase and amyloglucosidase in controlled-pore glass particles of two different pore sizes. The experimental results have been analyzed, initial-stage analysis for the rate parameters of immobilization reactions and long-time analysis for determining the evolution of the immobilization process. These investigations suggest that the overall process of immobilization is controlled by the restricted diffusion of enzymes into the pores of the support. As a result, immobilized enzyme (IME) can penetrate only up to a certain distance into the support. The penetration depth of IME for the support-enzyme system mentioned have been evaluated from the experimental bulk enzyme concentration data in a batch recirculation reactor.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 842-851 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Immobilization experiments have been performed with glucose oxidase as enzyme and controlled-pore glass of different pore sizes as support for chemical coupling. The experimental results have been analyzed for comparison with the theoretical model predictions. Analysis of the initial stage of the process gives the fundamental characteristic of the immobilization reaction. These investigations allow us to study the influence of the degree of diffusional restriction on the evolution of the immobilization process and spatial distribution of immobilized enzyme. Nonuniformly distributed concentrations have been achieved within the porous matrix, and suggestions have been made in designing such profiles by choosing appropriate experimental parameters.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 963-975 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A general theory is presented in this article for determining the intrinsic rate constants for the main reaction and deactivation reaction, the effective diffusivity of the substrate, and the active enzyme distribution within porous solid supports from deactivation study of a continuous stirred-basket reactor (CSBR). For the parallel deactivation five reaction kinetics are considered: (a) Michaelis-Menten, (b) substrate inhibition, (c) product inhibition (competitive), (d) product inhibition (anticompetitive), and (e) zero-order kinetics. The experimental results of the system of hydrogen-peroxide-immobilized catalase on controlled-pore glass particles are analyzed to demonstrate the application of the theory developed for parallel deactivation of active immobilized enzyme (IME). For series deactivation only first-order kinetics is treated, and a numerical procedure is proposed to deter mine the rate parameters and the internal active enzyme distribution. The experimental data of the system of glucose-immobilized glucose oxidase on silica-alumina and controlled-pore glass particles are used to verify the theory.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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