Immobilization of lipases onto the halogen & haloalkanes modified SBA-15: Enzymatic activity and glycerolysis performance study

Abstract

In this study, SBA-15 was modified by halogen & haloalkanes and later used to immobilize lipases. The hydrolysis activity and the glycerolysis performance of the immobilized lipases was carefully studied. Highest activity of the immobilized Candida antarctica lipase B (CALB), Lipase from Aspergillus oryzae (AOL), Lecitase® Ultra (LU) and lipase from Rhizomucor miehei (RML) was respectively at 5577, 12000, 2822 and 11,577 U/g; in addition, the highest activity was obtained from the lowest or moderate lipase loading, at 25.73, 90.72, 89.52 and 30.56 mg/g respectively. The mechanism of lipase immobilization was studied and it was through interfacial activation. The halogen & haloalkanes modification of SBA-15 afforded considerable glycerolysis activity for diacylglycerols (DAG) preparation. CALB@SBA-15-CH₂CH₂(CF₂)₅CF₃ and CALB@SBA-15-CH₂CH₂(CF₂)₇CF₃ were suitable for DAG production, they both exhibited good reusability in glycerolysis reaction, with 117.36% and 93.06% of their initial glycerolysis activity retained respectively after ten cycles of reuse. The relationships between temperature with triacylglycerols (TAG) conversion were lnV₀ = 3.13-3.07/T and lnV₀ = 7.90-4.64/T respectively for CALB@SBA-15-CH₂CH₂(CF₂)₅CF₃ and CALB@SBA-15-CH₂CH₂(CF₂)₇CF₃; in addition, their activation energy (Ea) was respectively at 25.50 and 38.54 kJ/mol.

Keywords: Glycerolysis; Halogen & haloalkanes modification; Immobilization; Lipase; SBA-15.