Trypsin was immobilized onto alginic acid-polyfglycidyl methacrylate) graft copolymer (AAGMA). The resulting immobilized enzyme showed 65% of the soluble enzymatic activity. The temperature optimum was shifted by 5°C to a higher value. The pH optimum of immobilized enzyme has also been shifted by 0.5 units toward the alkaline side when compared to that of soluble enzyme.The pH stability and thermal stability are better than that of soluble enzyme.

To synthesize a matrix for the immobilization of enzymes, alginic acid, a naturally occurring polysaccharide has been chosen as the backbone, and glycidyl methacrylate (GMA) and 2‐hydroxy ethyl methacrylate (HEMA) as monomers for graft copolymerization. HEMA was used to introduce hydrophilic character which would have been lost during the introduction of the hydrophobic monomer glycidyl methacrylate into alginic acid. Immobilization of trypsin onto this matrix takes place by covalent bonding. The temperature optimum of the immobilized enzyme was found to be 35°C and it was most stable at pH 8.

A method of enzyme immobilization by graft copolymerization onto alginic acid is reported. Glycidylmethacrylate along with methyl methacrylate was used as a vinylating reagent. The enzyme trypsin has been chosen for our studies. The effects of various parameters such as pH optima, temperature optima, pH stability, thermal stability, storage stability, and re‐usability were studied.