Dry entrapment of enzymes by epoxy or polyester resins hardened on different solid supports

Embedding of enzymes was performed with epoxy or polyester resin by mixing in a dried enzyme preparation before polymerization was started. This fast and low-cost immobilization method produced enzymatically active layers on different solid supports. As model enzymes the well-characterized Thermomyces lanuginosus lipase and a new threonine aldolase from Ashbya gossypii were used. It was shown that T. lanuginosus lipase recombinantly expressed in Aspergillus oryzae is a monomeric enzyme with a molecular mass of 34kDa, while A. gossypii threonine aldolase expressed in Escherichia coli is a pyridoxal-5'-phosphate binding homotetramer with a mass of 180kDa. The enzymes were used freeze dried, in four different preparations: freely diffusing, adsorbed on octyl sepharose, as well as cross-linked enzyme aggregates or as suspensions in organic solvent. They were mixed with standard two-component resins and prepared as layers on solid supports made of different materials e.g. metal, glass, polyester. Polymerization led to encapsulated enzyme preparations showing activities comparable to literature values.