TiO 2 nanofibers with uniform diameter about 125 nm were prepared based on sol-gel process and electrospinning technology. Protex 6L, an industrial alkaline protease, was covalently immobilized on TiO 2 nanofiber through γ-aminopropyltriethoxysilane modification and glutaraldehyde crosslinking. With 2 (v/v)% glutaraldehyde as crosslinker, the enzyme loading is about 201 mg (g nanofiber membrane) -1, and the specific activity of the immobilized Protex 6L is 2. 45 μmol h -1 ml -1 mg -1 protein for synthesis of sucrose monolaurate from sucrose and vinyl laurate. The optimal condition for sucrose monolaurate production is 5% (v/v) water content in DMSO/2-methyl-2-butanol solvent mixture and 50°C. Under this condition, 97% conversion was achieved within 36 h by nanofibrous Protex 6L, which is corresponding to a productivity 34 times higher than that of most widely used Novozym 435. After 10 cycles reuse, nanofibrous Protex 6L retained 52. 4% of its original activity.
Bibliographical noteFunding Information:
Acknowledgments 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.
- Enzyme immobilization
- Protex 6L
- Sucrose monolaurate
- TiO nanofiber