A Novel 3D Microflow Support for the Immobilization of Phospholipase D and Efficient Biphasic Transphosphatidylation.

A large-sized 3D microflow support was prepared by chemical liquid deposition of an epoxy-based porous polymer within a 3D melamine sponge. This novel support demonstrated advantages over traditional microfluidic reactors in terms of easier scalability, simplified enzyme loading, and superior multiphase dispersion. The resultant composite sponge was utilized as a microflow support for the immobilization of phospholipase D (PLD) through an adsorption and cross-linking method. Under optimal immobilization conditions, the loading capacity and specific activity of the immobilized PLD were 50.2 mg/g support and 14.5 U/mg protein, respectively. The PLD-immobilized microflow supports were positioned in a columnar reactor, where a biphasic transesterification reaction was conducted in a continuous circulation mode powered by two pumps. The PLD-catalyzed reaction yielded phosphatidylserine (PS) with high yields and reaction ratios. Under optimized conditions, the PS yield reached as high as 93.1% within 4 h at 45 °C, by using free PLD the PS yield reached only 61.5% within 12 h. After 10 cycles, the immobilized PLD retained 76% of its original activity.