Fabrication of Nanomaterial-Immobilized Lipase Enables Robust Enzymatic Interesterification: Lipid Characteristics and Underlying Catalytic Mechanism

The precise regulation of enzyme conformation through the immobilization of enzymes on carriers using sewing techniques represents a key focus in the site-specific chemically modification engineering. Lipase-mediated enzymatic interesterification (EIE) is of considerable significance in lipid chemistry, having demonstrated substantial potential in the modification of lipids. In this study, we developed an innovative nanomaterial Fe₃O₄-SiO₂-APTES for site-specific immobilization of Thermomyces lanuginosus lipase (TLL), achieving an immobilization yield of 51.98% and an enzyme loading capacity of 123.18 mg/g. The specific activity of the enzyme was 1034.09 U/g following lyophilization, representing increases of 2.6-fold compared to free TLL. The as-prepared biocatalyst TLL@Fe₃O₄-SiO₂-APTES exhibited enhanced catalytic activity, remarkable tolerance to organic solvents, substrate selectivity, and recyclability over multiple cycles. Rice bran oils (RBO) and palm stearin (PS) were employed as substrates for EIE, yielding oils with better performance of solid fat content (SFC), crystallization rate, and thermodynamic properties compared to those of physical blending oils. Additionally, we investigated the catalytic mechanism of EIE using molecular docking analysis. The present study provides a theoretical foundation for the application of immobilized lipase as biocatalysts in food industrial settings.

Practical Application: TLL@Fe₃O₄-SiO₂-APTES, modified at specific sites using nanomaterials, not only enhances the catalytic efficiency of the enzyme but also facilitates its reuse across multiple batches. This fixed enzyme could effectively catalyze the transesterification between PS and RBO, resulting in high-quality of oils specifically designed for baking foods. The findings in this study provide valuable guidance for the green processing of oils and fats.