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

Abstract

Microenvironment modification within nanoconfinement can maximize the catalytic activity of enzymes. Phospholipase A1 (PLA1) has been used as the biocatalyst to produce high value L-α-glycerylphosphorylcholine (L-α-GPC) through hydrolysis of phosphatidylcholine (PC). We successfully developed a simple co-precipitation method to encapsulate PLA1 in a metal–surfactant nanocomposite (MSNC), then modified it using alkalescent 2-Methylimidazole (2-Melm) to promote catalytic efficiency in biphasic systems. The generated 2-Melm@PLA1/MSNC showed higher catalytic activity than PLA1/MSNC and free PLA1. Scanning electron microscopy and transmission electron microscopy showed a typical spherical structure of 2-Melm@PLA1/MSNC at about 50 nm, which was smaller than that of 2-Melm@MSNC. Energy disperse spectroscopy, N2 adsorption isotherms, Fourier transform infrared spectrum, and high-resolution X-ray photoelectron spectroscopy proved that 2-Melm successfully modified PLA1/MSNC. The generated 2-Melm@PLA1/MSNC showed a high catalytic rate per unit enzyme mass of 1.58 μmol mg-1 min-1 for the formation of L-α-GPC. The 2-Melm@PLA1/MSNC also showed high thermal stability, pH stability, and reusability in a water–hexane biphasic system. The integration of alkaline and amphiphilic properties of a nanocomposite encapsulating PLA1 resulted in highly efficient sequenced reactions of acyl migration and enzymatic hydrolysis at the interface of a biphasic system, which cannot be achieved by free enzyme.

Enzymatic preparation of glycerophosphatilcholine catalyzed by combinational phospholipases: a comparative study of concertedversusstepwise catalysis

“…Li et al also discovered that high stirring rate could result in the reduction of catalytic activity. 38 In theory, with the increase of stirring rate, the interface area of substrate at the aqueous phase gradually increases, and the probability of phospholipase active sites on phospholipids also increases, which is benecial to the increase of the GPC yield. However, high stirring rate will make the reaction mixture and phospholipases suffer too much centrifugal force, resulting in being thrown to the inner wall of the reactor and reducing the GPC yield.…”

Two-stage Enzymatic Hydrolysis of Soybean Concentrated Phospholipid to Prepare Glycerylphosphorylcholine: Optimized by Response Surface Methodology

“…The results could be explained that high stirring rate increases the interface area of SCP at the aqueous phase and the probability of phospholipase active sites on SCP, resulting in the increase of the GPC yield. However, when stirring rate is too high, the centrifugal force on the SCP-water mixture and phospholipase is so large that they are thrown onto the inner wall of the reactor, which reduces the amounts of SCP-water mixture and phospholipase in the reaction, and slightly reduces the GPC yield 32 . Thus, the stirring rate was preferably 500 rpm.…”