Enzyme immobilization with a protein carrier

The process for the preparation of an immobilized enzyme composition which comprises dissolving a water-soluble protein in water to form a solution, adding a crosslinking agent to the solution to crosslink the protein and form a gel, drying the gel by heating to form a dried insoluble crosslinked protein having a water-absorption capacity of 2 to 8 times its dry weight, mixing the dry insoluble crosslinked protein with an enzyme-containing solution, allowing the insoluble cross-linked protein to swell and completely suck up the total amount of enzyme solution mixed with the dry insoluble crosslinked protein, and mixing the enzyme-containing swollen insoluble crosslinked protein with a solution of glutardialdehyde in a lower aliphatic alcohol or ketone to provide 0.5 to 5% glutardialdehyde in the resultant reaction mixture to bond the enzymes to the swollen insoluble crosslinked protein to provide the immobilized enzyme composition.