Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 110331
Title Cephalexin synthesis by immobilised penicillin G acylase under non-isothermal conditions: reduction of diffusion limitation
Author(s) Schroën, C.G.P.H.; Mohy Eldin, M.S.; Janssen, A.E.M.; Tramper, J.
Source Journal of Molecular Catalysis. B, Enzymatic 15 (2001). - ISSN 1381-1177 - p. 163 - 172.
Department(s) Sub-department of Food and Bioprocess Engineering
Publication type Refereed Article in a scientific journal
Publication year 2001
Abstract The effect of thermodialysis on the enzymatic kinetic synthesis of the antibiotic cephalexin was investigated. As reference points, two existing models for an immobilised enzyme (Assemblase?) and for the free enzyme were used. For Assemblase?, it is known that diffusion limitation occurs and that therefore considerably more of the undesired side-product phenylglycine is formed. The enzyme was immobilised on a membrane, and under isothermal conditions (293 K) the course of the reaction resembled that of the Assemblase? enzyme. However, if a temperature gradient was applied across the membrane, with an average temperature of 293 K for the enzyme, than the course of the reaction changed. For large temperature gradients (30° and more), the course of the reaction resembled that of free enzyme. Thermodialysis enhances mass transfer across the membrane and therewith reduces diffusion limitations in the immobilised enzyme on the membrane. The stability of the immobilised enzyme is such that the reactor can be re-used repeatedly. This, together with the positive effect of the temperature gradient on the course of the reaction, makes thermodialysis an interesting new technique that has potential to be applied on a larger scale if the membrane surface area per volume of reactor can be improved.
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