Hyperactivation of lipase by oil-water interface in interfacial immobilization on hierarchical porous hollow silica microsphere: dynamics, mechanism and application

Abstract

Lipases exhibit high activity at oil−water interfaces due to interfacial activation effect. In this work, the interfacial immobilization of lipase was developed based on Pickering emulsion through using lipase solution as the aqueous phase, n-hexane as oil phase, and stabilized by modified hierarchical porous hollow silica microsphere (HPHSM-C1). The prepared immobilized lipase HPHSM-C1@AY400-II achieved highest specific activity (6.4 IU/mg) with the amount of immobilized protein of 34.5 mg/g, surpassing traditional adsorptive immobilized lipase (HPHSM-C1@AY400) by 1.89-fold, and retained 70 % of residual activity after ten operational cycles. The conformational change of HPHSM-C1@AY400-II was confirmed by Fourier transform infrared. The interfacial adsorption at oil-water interface was influenced by intraparticle and surface diffusion, as evidenced by adsorption kinetic. Finally, the HPHSM-C1@AY400-II was applied in enzymatic enrichment of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) in glycerides, and the content of ω-3 PUFAs in the glyceride significantly increased from 32.35 % to 54.78 % after 3 h of selective hydrolysis. This study opens a promising avenue to improve lipase activity in immobilization process, contributing to enzymatic synthesis of functional lipids.