Immobilization as a Tool for Improving Enzymes

The application of enzymes as catalysts in organic chemistry is closely linked to their immobilization. Indeed, many enzymes are only available in an immobilized form. The immobilized enzymes can be used as received, greatly easing their application. Numerous of these readily available immobilized enzymes are now the working horses of biocatalysis. This has even led to the incorrect use of the abbreviation of an enzyme name for a specific enzyme preparation, that is CALB for the immobilized form of Candida antarctica lipase B on cross-linked polymethacrylate (also known as Novozym 435). Vice versa the commercial name of an enzyme preparation-Amano PS-has taken the place of the enzyme (Burkhdderia cepacia lipase on dextrin or diatomaceous earth). Surprisingly, often no attention is paid to the fact that the enzyme is immobilized [1]. 

For enzymes another point can be important Not all pure enzymes are stable in solution. In particular in organic solvents enzymes can be very unstable (4). The stability of enzymes can be improved by genetic modifications, by chemical modification, and most easily and without specialist equipment by immobilization. Furthermore, immobibzation opens up the possibility of improving other properties of the enzyme, such as its activity, substrate specificity, and enantioselectivity. Although the underlying principles are not always understood enzyme immobilization is a powerful tool for the improvement of activity and enzyme stability, specificity, and selectivity. 

Modem Biocatalpis Stereoselective and Environmentally Friendly Reactions. Edited by Wolf-Dieter Fessner and Thorleif Anthonsen Copyright 2009 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-32071-4 

Advantages Mild reaction conditions Excellent separation 

Disadvantages Difficult separations Heat transfer problems 

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