Alkaline Modification of a Metal–Enzyme–Surfactant Nanocomposite to Enhance the Production of L-α-glycerylphosphorylcholine

Enhancing Soluble Expression of Phospholipase B for Efficient Catalytic Synthesis of L-Alpha-Glycerylphosphorylcholine

Phospholipase B (PLB) harbors three distinct activities with broad substrate specificities and application fields. Its hydrolyzing of sn-1 and sn-2 acyl ester bonds enables it to catalyze the production of L-alpha-glycerylphosphorylcholine (L-α-GPC) from phosphatidylcholine (PC) without speed-limiting acyl migration. This work was intended to obtain high-level active PLB and apply it to establish an efficient system for L-α-GPC synthesis. PLB from Pseudomonas fluorescens was co-expressed with five different molecular chaperones, including trigger factor (Tf), GroEL-GroES (GroELS), DnaK-DnaJ-GrpE (DnaKJE), GroELS and DnaKJE, or GroELS and Tf or fused with maltose binding protein (MBP) in Escherichia coli BL21(DE3) to improve PLB expression. PLB with DnaKJE-assisted expression exhibited the highest catalytic activity. Further optimization of the expression conditions identified an optimal induction OD600 of 0.8, IPTG concentration of 0.3 mmol/L, induction time of 9 h, and temperature of 25 °C. The PLB activity reached a maximum of 524.64 ± 3.28 U/mg under optimal conditions. Subsequently, to establish an efficient PLB-catalyzed system for L-α-GPC synthesis, a series of organic-aqueous mixed systems and surfactant-supplemented aqueous systems were designed and constructed. Furthermore, the factors of temperature, reaction pH, metal ions, and substrate concentration were further systematically identified. Finally, a high yield of 90.50 ± 2.21% was obtained in a Span 60-supplemented aqueous system at 40 °C and pH 6.0 with 0.1 mmol/L of Mg2+. The proposed cost-effective PLB production and an environmentally friendly PLB-catalyzed system offer a candidate strategy for the industrial production of L-α-GPC.

Special Issue “Biocatalysts: Design and Application”

The use of biocatalysts in chemical reactions is of great interest because reactions can be carried out under very mild and green conditions [...]

Enzymatic preparation of glycerophosphatilcholine catalyzed by combinational phospholipases: a comparative study of concerted versus stepwise catalysis

Glycerophosphatilcholine (GPC) is widely applied in medical, pharmaceutical, food and cosmetic industries. Due to the lack of natural resources, enzymatic preparation of GPC has been explored in recent years. This study aimed to investigate and compare the effects of different addition methods of combinational phospholipases (PLA₁ and PLA₂) and various process parameters (time, temperature, pH, substrate concentrate, enzyme load, and stirring rate) on the preparation of GPC. The results showed that compared with concerted catalysis, the catalytic efficiency of adding PLA₂ and then PLA₁ (PLA₂ → A₁) was higher, whereas that of adding PLA₁ and then PLA₂ was lower. The main reason might be that the method of PLA₂ → A₁ could reduce acyl migration and the competition between PLA₁ and PLA₂, which was beneficial to improve the GPC yield and shorten the reaction time. This paper could provide a novel approach for the future preparation of GPC catalyzed by combinational phospholipases.

The addition methods of PLA₁ and PLA₂ had a vital influence on the preparation of GPC, and the method of PLA₂ → A₁ was the most effective.