An alkaline protease from Bacillus licheniformis, Protex 6L, was used for synthesis of sucrose monolaurate from sucrose and vinyl laurate in a tert-amyl alcohol/DMSO/water solvent mixture. Introducing sucrose as powder after mixing vinyl laurate with solvent mixture resulted in a higher reaction rate than when sucrose was added as a solution in DMSO. Response surface methodology (RSM) was applied to optimize the major reaction variables, water content, temperature and pH of the lyophilized enzyme. The optimal conditions derived from RSM (3.4% water content, 43 °C and pH of 10.1) provided a high initial reaction rate of 8.66 ± 0.3. mg/ml/h which agreed with the predicted value of 8.70. mg/ml/h. With 1.5. mg-enzyme/ml, 98.0% of the added sucrose was region-selectively converted to 1'-O-lauroylsucrose after 9. h. Under the optimized conditions, Protex 6L exhibited a higher productivity for sucrose ester synthesis than Novozym 435 and three other commonly used enzymes.
Bibliographical noteFunding Information:
The authors thank support from the National Natural Science Foundation of China (Grant No. 20728607 , 20706054 , 20976180 ), 973 Program (2009CB724705) and 863 Project (2008AA10Z302). We are also grateful to Genencor International for providing us with the Protex 6L.
- Protex 6L
- Response surface analysis
- Solvent mixture
- Sucrose monolaurate