Hydrolysis of β‐galactosides using polymer‐entrapped lactase. A study towards producing lactose‐free milk

Abstract A yeast lactase, Maxilact, was immobilized in crosslinked polyacrylamide using a bead‐polymerization technique. The polymer beads obtained, containing the entrapped enzyme, were used for the preparation of lactose‐free milk. The binding yield of the enzyme and residual enzymic activity in the “enzyme beads” were studied as a function of the amounts of monomeric acrylamide and cysteine and bovine serum albumin present as protecting agents in the monomer‐enzyme solution prior to polymerization. A maximum of about 75% of the enzyme could be immobilized using a 20% (w/v) solution of acrylamide plus N, N′‐methylenebis‐acrylamide, whereas the highest activity quotient (bound to free) of about 60% was observed on using a 25% solution. The presence of cysteine increased the activity by up to 30% and that of serum albumin up to about 15%.