Immobilization of lipase on mesoporous silica nanocarriers for efficient preparation of phytosterol esters.

Phytosterol esters (PEs) are favored for their good solubility, high bioavailability, and various health benefits. Mesoporous silica (MS) nanocarriers were synthesized and utilized to immobilize free lipase AYS "Amano" (from Candida rugosa) for further preparing PEs. The optimal immobilization conditions were an initial enzyme content of 160 mg/mL, pH of 7.0, temperature of 30 °C, and adsorption time of 6 h, resulting in a protein loading of 42.3 mg/g and an immobilization efficiency of 73.4 %. Compared to commercial carriers, MS carriers demonstrated superior immobilization efficiency and phytosterol conversion rates when soybean oil was used as the PEs source for the transesterification. The phytosterol conversion rate reached 97.7 % in a solvent system with optimal reaction conditions. After 30 days of storage, the immobilized lipase retained 55.7 % of its activity, and it had 63.0 % retention activity after 10 reuse cycles. This study significantly enhanced the lipase's phytosterols conversion and reusability, supporting sustainable and efficient industrial production of PEs.