Catalytic synthesis of galactooligosaccharides by K.fragilis β-D-galactosidase immobilized on epoxy carrier

The carrier with active epoxy group was prepared by suspension polymerization.Effect of initial enzyme concentration and reaction time on the K.fragilis β-D-galactosidase immobilization efficeiency was evaluated, and the factors which influenced the synthetic amout of galactooligosaccharides by immobilized K.fragilis β-D-galactosidase were researched.The results showed that the prepared epoxy group carrier was single scattered and approximate spherical spheres with particle size about 150²00μm.When initial enzyme concentration was 3.0mg/mL, the quantity of immobilized K.fragilis β-D-galactosidase, which has the higher recovery of immobilized enzyme activity 70%, achieved the maximum (69.8mg/g) .With immobilized time increased, The amount of immobilized enzyme increased and reached the maximum at 10h .Under the optimum condition (substrate concentration:150g/L, reaction time:4h) , the yield of GOS synthetized by immobilized K.fragilis-β-D-galactosidase enzyme was the best.