Enhancement of Rhizopus oryzae lipase activity immobilized on alkyl-functionalized spherical mesocellular foam: Influence of alkyl chain length

Spherical silica-based mesocellular foam (MCF) with pores of average size 22 nm interconnected by 11.8 nm windows was synthesized and then functionalized with alkyl groups using propyl-, butyl-, octyl- and octadecyltrimethoxysilane. Rhizopus oryzae lipase (ROL) was immobilized on MCF and alkyl-functionalized MCF (alkyl-MCF) by physical adsorption. The transesterification reaction activity of (S)-glycidol and vinyl n-butyrate using ROL immobilized on alkyl-MCF increased with increase in alkyl chain length, implying that the more hydrophobic the microenvironment, the greater the activation of ROL. The specific activity of transesterification reaction by ROL immobilized on C18-MCF was 73 times higher than that of free ROL. ROL immobilized on C18-MCF could be reused for eight batches without significant loss of activity.