Biosynthesis of sucrose-6-acetate catalyzed by surfactant-coated Candida rugosa lipase immobilized on sol-gel supports.

Sucrose-6-acetate is an important intermediate in the preparation of sucralose (a finest sweetener). In our study, Candida rugosa lipase coated with surfactant was firstly immobilized on sol-gel supports. Then, the immobilized enzyme was used in the regioselective synthesis of sucrose-6-acetate by transesterification of sucrose and vinyl acetate. The screening results revealed that Tween 80 was an ideal surfactant to coat lipase immobilized in sol-gel and exhibited the highest yield of sucrose-6-acetate. Other factors that influenced the yield during the preparation process were also studied. Under optimal conditions, the yield of sucrose-6-acetate could reach up to 78.68 %, while free lipase was easily inactivated in polar solvent. Thermal and operational stabilities were also improved significantly. Surfactant-coated lipase immobilized in sol-gel remained stable when the temperature was higher than 60 °C. Moreover, they could maintain high catalytic activity after six recycles. This strategy is economical, convenient and promising for the food industry.