Enzymatic synthesis of phosphatidyl-EPA/DHA using Candida antarctica lipase B immobilized on mesoporous MIL-88 A

Abstract Mesoporous MIL-88A (Meso-MIL-88A) shows significant potential as an effective carrier for immobilizing large molecules such as lipases. This study investigates Meso-MIL-88A immobilized lipase for the catalysis of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) incorporation into soybean phosphatidylcholine. Phosphatidyl-EPA and phosphatidyl-DHA are known for their superior health benefits and have garnered significant global attention. Firstly, we developed a novel and green water-washing strategy to synthesize Meso-MIL-88A, demonstrating its significant potential as an effective carrier for immobilizing large molecules such as lipases. Nitrogen adsorption/desorption and XPS analyses revealed that water as the eluent yielded larger average pore diameters and lower sulfur residue content compared to ethanol. This optimized Meso-MIL-88A carrier was used to immobilize Candida antarctica lipase B (CalB@Meso-MIL-88A), which was applied to the production of phosphatidyl-EPA and phosphatidyl-DHA. The immobilized CalB@Meso-MIL-88A exhibited exceptional catalytic efficiency, achieving an unprecedented sn-1 positional incorporation rate of 86.8% (44.2% EPA, 42.7% DHA) with 90% EPA/DHA-ethyl ester (EE) donors, while 97% DHA-EE resulted in a record-high 90.1% DHA incorporation at the sn-1 position. Kinetic studies and molecular docking simulations indicated a higher substrate affinity for DHA-EE, attributed to enhanced transfer efficiency of EPA/DHA-EE in organic solvent system. This study presents the first demonstration of the potential of Meso-MIL-88A for industrial lipase immobilization via this optimized route, offering an eco-friendly and highly efficient catalytic application for nutraceutical synthesis. Graphical abstract