Encapsulating Enzymes Within Pickering Emulsion-Derived Microcapsules for Continuous-Flow Epoxidation of Vegetable Oils

Abstract

Enzyme-catalyzed transformation of vegetable oils into epoxidized vegetable oils (EVOs) is of significant importance for sustainable and green industrial production. However, challenges such as enzyme inactivation, low efficiency, and poor stability hinder its large-scale implementation. In this study, a continuous-flow catalytic system based on enzyme-encapsulated Pickering emulsion microcapsules was developed to address these issues. Candida antarctica lipase B (CALB) was encapsulated within microcapsules featuring porous silica shells, forming a stable aqueous microenvironment that maintains enzyme conformation and activity. This design also prevents droplet agglomeration and ensures stability in polar reaction media. By adjusting the structure of microcapsules and reaction conditions, including microcapsules size, shells thickness, enzyme content, and hydrogen peroxide concentration, the optimal conditions for the epoxidation reaction are identified. Utilizing these conditions, the system achieved 80%–92% conversion for the epoxidation of various vegetable oils, maintained long-term operational stability for up to 700 h, and exhibited a fivefold increase in specific activity compared to traditional batch systems. This study provides a novel and industrially viable approach to the epoxidation reaction of vegetable oils.