Enzyme immobilization on graft copolymers

M.S. Mohy Eldin

    Research output: Thesisinternal PhD, WU


    <p>Immobilised enzymes can be reused, easily separated from the reaction medium, and are more stable in most of the cases. Despite of these advantages, there are still some problems facing the usage of the immobilised enzyme in industry. One of those problems is diffusion-limitation of both the reactants and the products. This problem becomes even more serious when the products are inhibitors of the enzymes. Different strategies for overcoming this problem have been discussed in this thesis.</p><p>A new solution to overcome diffusion limitation is based on processing the enzymatic reaction under non-isothermal conditions. In such a bioreactor the enzymes have to be immobilised on a hydrophobic membrane.</p><p>In this thesis, two enzymes,β-galactosidase and penicillin G acylase have been immobilised onto teflon and nylon membranes. Two grafting techniques have been used to modify the membranes in order to be able to bind the enzyme. These grafting techniques were based on using high-energy radiation as well as chemical modification. Both the grafting technique and enzyme immobilisation method has been optimised. The performance of the membranes has been tested in the non-isothermal bioreactor. A higher activity under non-isothermal conditions was found in comparison to isothermal operation. Furthermore, the application of the non-isothermal conditions is promising for solving the diffusion-limitation problems.</p>
    Original languageEnglish
    QualificationDoctor of Philosophy
    Awarding Institution
    • Tramper, J., Promotor, External person
    • Mita, D.G., Promotor, External person
    • Janssen, Anja, Promotor
    Award date29 Nov 1999
    Place of PublicationS.l.
    Publication statusPublished - 1999


    • enzymes
    • immobilization
    • membranes


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