Treatments for preparing castable ceramic surfaces for enhanced bonding to specially formulated resin-based cements were examined. An ammonium bifluoride etch combined with gamma-methacryloxypropyl-trimethoxysilane produced shear bond strengths higher than when an ammonium bifluoride treatment was used alone. The method of curing the silane was highly significant in the contribution to the cement/substrate bond strength, with the heat-cure producing the highest values. Long-term water storage tests indicated that the cement bond with etch plus silane-treated castable ceramic surfaces (whether heat or chemically cured silane was used) demonstrated no significant decrease in strength after a one-year period.

The immobilization of enzymes, cofactors and whole cells offers the potential of economical exploitation of biomaterial activity. Enzymes or cells can be immobilized by binding to carriers through adsorption or covalent linkages or by entrapment in a polymer matrix or microencapsulation. The development of immobilized biomaterial systems requires the involvement of biochemical, kinetics and reactor design principles. Examples of commercial scale applications of immobilized biomaterial systems are the production of a fructose-rich syrup from starch and the synthesis of L-amino acids by selective hydrolysis of N-acyl-D,Lamino acids.

Die Immobilisierung von Enzymen, Cofaktoren und ganzen Zellen bietet die Möglichkeit, die Aktivität von Biomaterialien ökonomisch zu nutzen. Zur Immobilisierung haben sich Adsorption und kovalente Bindung an hochmolekulare Träger sowie Einschluß in Polymere und Mikroverkapselung bewährt. Will man Systeme mit immobilisierten Biomaterialien entwickeln, muß man sowohl biochemische und kinetische als auch apparative Aspekte berücksichtigen. Beispiele für großtechnische Anwendungen sind die Gewinnung von Fructose‐reichem Sirup aus Stärke und die Herstellung von L‐Aminosäuren durch selektive Hydrolyse von N‐Acyl‐DL‐aminosäuren.

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