Immobilization of glucoamylase and trypsin on crosslinked thermosensitive carriers

In this paper the immobilization of glucoamylase and trypsin on thermosensitive copolymers of N-isopropylacrylamide and 2-hydroxyethyl methacrylate or glycidyl methacrylate modified by amination is evaluated. The method is based on the swelling properties of these stimuli-sensitive polymers. On cooling the polymers expand and work like a pump that sucks up the enzyme adsorbed onto their surface and then the enzyme is cross-linked with glutaraldehyde, thus forming an interpenetrated polymer network. The attention was focused on the properties of the carrier–enzyme systems, particularly on the effect of cross-linking on their storage stability. The data obtained for unmodified thermosensitive carriers and carriers hydrophilised with ethylenediamine were compared. In the case of both enzymes, TH8-NH2 carrier is the most suitable, as the highest activity of immobilized enzymes is retained. Low molecular weight substrates are preferred in both cases.