Study on Isoflavone Active Aglycone Preparation by Immobilized β-glucosidase from Aspergillus niger

Abstract:

With sodium alginate as a carrier and glutaraldehyde as the crosslinking agent, an improved immobilization method of β-glucosidase for production of soybean genistein was developed. As compared with entrapment or entrapment-crosslinkage, crosslinkage-entrapment that β-glucosidase was treated with glutaraldehyde and then entrapped in sodium alginate remained high loading efficiency and activity recovery, Effects of bead sizes, concentrations of alginate and glutaraldehyde as well, on the loading efficiency and activity recovery were assessed. When compared with the free enzyme, the optimum temperature, pH value and K_m of the immobilized β-glucosidase were respectively shifted from 50℃ to 40℃, 4.5 to 4.0 and 2.57 μg/mL to 2.02 μg/mL. The stabilities of the immobilized β-glucosidase were considerably better than that of the native enzyme. The immobilized β-glucosidase was employed to genistein production, 84.94% of the activity and 56.04% of conversion were kept after consecutive use of 6 times.