Enhanced Pickering interfacial biocatalysis in phosphatidylserine synthesis via phospholipase D immobilization with optimized bifunctional strategy

Phosphatidylserine (PS) is a high-value phospholipid in functional foods and pharmaceuticals. However, the lack of a suitable biocatalytic system has limited the conversion efficiency. A novel Pickering interfacial biocatalysis (PIB) system has developed for converting phosphatidylcholine (PC) to PS in this work. Three immobilized enzyme carriers were synthesized by grafting different modifying groups onto hollow mesoporous silica particles (HMSP). The combination of NQ-62 and octyl-modified groups yielded the optimal immobilized enzyme, PLD@HMSP-N₃/C₈. It stabilized the water-in-oil Pickering emulsion and enhanced phospholipase D (PLD) stability via hydrogen bond interactions. Under optimized conditions, a PS conversion of 93.8 % was achieved within 20 min at 40 °C, achieving a catalytic efficiency (CE) of 372 mmol/(g·h). The immobilized PLD demonstrated markedly enhanced thermostability, pH resistance, and protease hydrolysis stability compared to its free and homologous series counterparts. Moreover, it retained 70.9 % of the PS conversion after 10 cycles of reuse.