Lipase Immobilized on Layer-by-Layer Polysaccharide-Coated Fe3O4@SiO2 Microspheres as a Reusable Biocatalyst for the Production of Structured Lipids

A promising strategy for lipase immobilization based on the natural polymers of polysaccharides (hyaluronan (HA) and chitosan (CHI)) functionalized magnetic microspheres (Fe3O4@SiO2@{CHI/HA}3) was developed. First, Fe3O4 magnetic microspheres and Fe3O4@SiO2 core/shell microspheres were synthesized by hydrothermal reaction and sol–gel method, respectively. Owing to the abundant carboxyl groups in HA chains, the lipase was covalently bonded on the surface of the polysaccharide-functionalized magnetic supports by ultilizing 1-ethyl-3-(3-(dimethylamino)-propyl) carbodiimide and N-hydroxysuccinimide chemistry to produce robust biocatalysts of Fe3O4@SiO2@{CHI/HA}3@lipase. The morphology, core–shell structure, and magnetic property of the supports and immobilized lipase were investigated through various analytical techniques, including FT-IR analysis, transmission electron microscopy, scanning electron microscopy equipped with energy dispersive spectrometer, elemental analysis, vibrating sample magnetometer, thermogravimetric analysis, and X-ray diffraction. Consequently, the magnetic Fe3O4@SiO2@{CHI/HA}3 microspheres exhibited a superior performance in terms of immobilizing lipase. The magnetic immobilized lipase showed good thermal and long-term stability, reusability, and catalytic activity for the synthesis of the structured lipid of 1,3-dioleoyl-2-palmitoylglycerol (OPO), which has recently received much interest as a healthy component of food, oil, and pharmaceutical intermediates. The magnetic immobilized lipase could be considered a green and sustainable biocatalyst for the highly efficient synthesis of OPO.