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The immobilized biocatalyst (IMB) is a key component of biotransformation systems that are used to transform substrates to desired products. The impro- ment of biocatalyst properties has a direct influence on the overall effectiveness of the process based on the biotransformation. The basic catalytic characte- stics of biocatalyst that are followed include kinetic properties, pH optima, stability,and inhibition. The investigation of catalytic properties of immobilized enzymes is still a time consuming procedure and is not always simple. In the 1980s,a major effort was made to standardize the rules by which IMB is char- terized. The Working Party of EFB on immobilized biocatalysts has formul- ed principles of individual methods, among them the requirement of kinetic characterization [1]. It was recommended to use a packed-bed reactor,equipped with temperature control and with infinite flow circulation. The system should be equipped with a post-column unit to measure the time-dependence of the product or substrate concentration [2, 3], the most commonly used analytical methods being spectrophotometry, chemiluminiscence, automatic titration, bioluminiscence, chromatography, polarimetry, and biosensors based on the oxygen electrode. There are two main drawbacks to the application of these methods: 1. The need to vary the analytical principles, depending on the chemical and physical-chemical properties of analytes; 2. In some cases, mainly in the study of hydrolytic enzymes, the natural s- strate must be replaced by an artificial one,that is chromolytic,chromogenic, chemiluminiscent,bioluminiscent,or fluorescent.

The immobilized biocatalyst (IMB) is a key component of biotransformation systems that are used to transform substrates to desired products. The impro- ment of biocatalyst properties has a direct influence on the overall effectiveness of the process based on the biotransformation. The basic catalytic characte- stics of biocatalyst that are followed include kinetic properties, pH optima, stability,and inhibition. The investigation of catalytic properties of immobilized enzymes is still a time consuming procedure and is not always simple. In the 1980s,a major effort was made to standardize the rules by which IMB is char- terized. The Working Party of EFB on immobilized biocatalysts has formul- ed principles of individual methods, among them the requirement of kinetic characterization [1]. It was recommended to use a packed-bed reactor,equipped with temperature control and with infinite flow circulation. The system should be equipped with a post-column unit to measure the time-dependence of the product or substrate concentration [2, 3], the most commonly used analytical methods being spectrophotometry, chemiluminiscence, automatic titration, bioluminiscence, chromatography, polarimetry, and biosensors based on the oxygen electrode. There are two main drawbacks to the application of these methods: 1. The need to vary the analytical principles, depending on the chemical and physical-chemical properties of analytes; 2. In some cases, mainly in the study of hydrolytic enzymes, the natural s- strate must be replaced by an artificial one,that is chromolytic,chromogenic, chemiluminiscent,bioluminiscent,or fluorescent.

Die Biotechnologie befindet sich augenblicklich in einem standigen Wandel. Dinge, die heute neu erscheinen, sind schon in Klirze veraltet. Grundsatze, Regeln und Be griffe andern sich standig oder werden von Arbeitskreis zu Arbeitskreis anders defi niert. Da die Zahl der Lehrbficher in der Biotechnologie noch immer recht klein ist, fehlt ein "solides biotechnologisches" Basiswissen. Zusammenfassende Studien fiber Teilgebiete der Biotechnologie sind notig, urn einen schnellen, intensiven Austausch neuer Forschungsbereiche und -ideen zu gewiihrleisten. Sie sollten eine Zusammen fassung der bisherigen relevanten Forschungsarbeiten beinhalten und so ein gewisses "Basiswissen" schaffen. Da ich mich im Rahmen meiner Habilitationsarbeit mit einem Teilgebiet der Bio technologie - der Beobachtung des Zellzustands und der Zellumgebung bei Biopro zessen - beschiiftigte und viele Ergebnisse aus der Literatur und der eigenen For schung beschrieben habe, erschien es mir einleuchtend, diese Erfahrungen im Rah men dieser Stu die einem breiteren Interessentenkreis zur Diskussion bereitzustellen. Die Studie kann nicht den Anspruch der Vollkommenheit erheben, gtbt aber sicher einen guten Oberblick zu dem Thema. Die Studie entstand auf der Basis meiner Habilitationsarbeit, die ich im Zeitraum von 1985 und Juli 1989 angefertigt habe. Ein GroBteil der in ihr beschriebenen For schung wurde am Institut fUr Technische Chemie der Universitat Hannover, ein Teil am Department of Chemical Engineering am California Institute of Technology (Pasadena, USA) betrieben."