Phosphatidylserine (PS) is a natural phospholipid with particular importance in the food, cosmetic, and pharmaceutical industries. Recently, the synthesis of PS mediated by phospholipase D (PLD) has drawn great attention. But the application of free PLD is limited by various drawbacks, including its instability under extreme conditions, difficulties in reuse and recovery, and high costs. In this work, saPLD-inorganic hybrid nanoflowers (saPLD@NFs) were synthesized with PLD from Streptomyces antibioticus (saPLD) as the organic component and Ca₃(PO₄)₂ as the inorganic component. The saPLD@NFs demonstrated outstanding immobilization capability and achieved a 119% enzyme activity recovery rate. Furthermore, the saPLD@NFs exhibited better thermostability and pH stability in comparison to free saPLD. The PS yield of saPLD@NFs was about 57.4% in the first cycles and still reached 60.4% of its initial PS yield after four cycles. After 25 d storage at 4 °C, saPLD@NFs retained 66.5% of its original activity, but free saPLD only retained 38.3%, indicating that saPLD@NFs have excellent storage stability. Thus, this study established a new method of preparing PLD nanoflowers for effective PS synthesis, which might accelerate the practical utilization of this biocatalyst.

As a natural phospholipid, phosphatidylserine (PS) plays a key role in the food, cosmetic, and pharmaceutical industries. Recently, substantial attention has been focused on the phospholipase D (PLD)-mediated synthesis of PS. However, the application of free PLD is usually limited by high cost, poor reusability, and low stability. In this study, PLD from Streptomyces antibiotics (saPLD) was efficiently immobilized on SiO₂ through physical adsorption to develop saPLD@SiO₂. The stability of the saPLD@SiO₂ was higher than that of the free saPLD over an extensive range of temperature and pH conditions. Furthermore, the PS yield of saPLD@SiO₂ was approximately 41% in the first cycles, and still kept 60% of its initial PS yield after 14 cycles. After a 25-day storage period, the saPLD@SiO₂ retained 62.5% of its initial activity, while the free saPLD retained only 34.3%, suggesting that saPLD@SiO₂ has better stability than free saPLD. A Pickering emulsion was produced by dispersing saPLD@SiO₂ in solutions (ethyl propanoate and acetate/acetic acid buffer) using ultrasound. The engineered Pickering emulsion demonstrated excellent catalytic activity, with a 62% PS yield after 6 h, while free saPLD had only 18%. The results indicated that a high-performance and sustainable biocatalysis method was established for the effective synthesis of PS.