Abstract: Glucoamylase is immobilized with a carbodiimide on a polymer having amino or carboxy functional groups. When the polymer contains amino groups, the glucoamylase is treated with the carbodiimide and then mixed with the polymer or the carbodiimide is added to a mixture of the glucoamylase and the polymer. When the polymer contains carboxy groups, the polymer is treated with the carbodimide and then mixed with the glucomylase. The polymer is produced from acrylic acid, metharylic acid, acrylamide, methacrylamide, N-amino-ethyl-acrylamide and/or N-amino ethyl methacrylamide and a cross-linking agent of the acrylic or allylic type.