Immobilization of trypsin on an enteric polymer Eudragit S-100 for the biocatalysis of macromolecular substrate

Abstract

Trypsin was covalently linked to Eudragit S-100 (an enteric coating polymer) by carbodiimide coupling method. Nearly 90% of enzyme activity was conjugated to the polymer whereas actual observed (expressed) activity was 64%. The enzyme bound to the polymer by simple adsorption as well but leached off the polymer in the presence of high ionic strength (1.0 M NaCl). The immobilized enzyme showed stability to autolysis at 45°C and had a marginal shift in pH optimum. The K m value of the enzyme decreased from 1.0×10 −3 M to 0.7×10 −3 M on immobilization. The soluble Eudragit-trypsin conjugate was used to hydrolyze casein at 45°C. Eudragit being a reversibly soluble–insoluble polymer, the biocatalyst could be recovered and reused.