Lipase immobilization on functionalized mesoporous TiO2: Specific adsorption, hyperactivation and application in cinnamyl acetate synthesis

Abstract According to the purification characteristics of lipase from Burkholderia ambifaria YCJ01, mesoporous TiO 2 was functionalized by phenylaminopropyl trimethoxysilane (Ph-TiO 2 ) for lipase immobilization. This support permitted one step immobilization and purification of lipase YCJ01 via hydrophobic interactions from crude fermentation supernatant. The activity of immobilized lipase was 6119.2 U/g support with 12.8 mg/g support of enzyme loading. The ratio of the activity of immobilized lipase to decrease activity in the supernatant after immobilization reached 2.2, which indicated that the immobilized lipase molecules exhibited a dramatic hyperactivation. In comparison with free lipase, immobilized lipase showed significantly improved pH stability and thermalstability. The Ph-TiO 2 /YCJ01 biocomposite was analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. The result indicated lipase was efficiently immobilized on Ph-TiO 2 surface. Finally, the research about cinnamyl acetate synthesis suggested that Ph-TiO 2 /YCJ01 had enhanced catalytic efficiency compared with free lipase. In solvent free medium, the yield of 96.9% was obtained after one operation, and maintained more than 80% of yield after ten reaction cycles.