Efficient synthesis of DHA/EPA-rich phosphatidylcholine using immobilized phospholipase A1 on a novel microflow support

Abstract

A new epoxy-based polymerizing/compositing synchronic process was carried out in 3D structure of a melamine sponge. The cured polymer formed a porous and wave-shaped coating on the surface of skeleton in a uniform way. The obtained composite sponge was used as a microflow support for the immobilization of phospholipase A1 (PLA1, from Thermomyces lanuginosus/Fusarium oxysporum) by co-adsorption/cross-linking with polyethylenimine (PEI). The loading amount and the specific activity of immobilized PLA1 under the optimal immobilization conditions were 45.7 mg/gsupport and 9.1 U/mgprotein. The PLA1-immobilized microflow supports were placed in a columnar reactor, in which transesterification was operated in continuous circulation way. The reaction produced DHA/EPA-incorporated phosphatidylcholine, the hydrolysis side reaction could be inhibited by removal of free water in the reaction medium. Under optimized conditions the incorporation percentage of DHA/EPA and PC yield of 54.3% and 82.4% within 18 h at 55 ℃, respectively. After 10 cycles, the immobilized PLA1 retained 71.2% of the original activity. The use of microflow support has an advantage on easier scaling up the reactor size towards much larger productivity and higher efficiency.