Stabilization of the activity of beta-galactosidase in permeabilized immobilized cells for hydrolysis of lactose in milk

A potentially low cost beta -galactosidase was prepared as a crude permeabi lized cell mass of the yeast Kluyveromyces lactis that had been grown in ul trafiltered cheese whey. The enzyme preparation was immobilized in alginate beads. Milk lactose hydrolysis rates were 25% higher in manganese alginate beads than in calcium alginate beads. The immobilized biocatalyst lost act ivity when stored in calcium chloride solution, however, storage in 5 mM DT T or 50% glycerol allowed the biocatalyst to be recycled at least 5 times w ithout any loss of activity.