Construction of Pickering Interfacial Catalytic System by Janus Nanoparticles and its Application in Enzymatic Synthesis Phytosteryl Oleate

Enzymatic catalytic had been attracted much attention due to its mild condition, fewer byproducts and environmental protection. However, low production capability, time consuming work and poor reusability limited the popularization of the process. To address these problems, in this study, in order to improve the application value of phytosteryl oleate, on the basis of traditional method of lipase-catalyzed synthesis, Janus nanoparticles were prepared and used to construct Pickering emulsion interfacial catalytic system as emulsifier in presence of lipase. The results showed that Janus nanoparticles could be used to stable stable water in isooctane emulsion and the average particle size of emulsion was 60 μm, phytosterol ester was successful synthesis in Pickering emulsion catalytic system by using oleic acids as acyl accepters, and the phytosterol conversion reached 91.65% under the following conditions: emulsifier amount of 1.0 wt%, oil-water ratio of 6:1, phytosterol concentration of 110 mmol/L, lipase dosage of 20 g/L, reaction temperature of 45 ℃. Compared with biphasic catalytic system, Pickering emulsion catalytic system enhance the catalytic efficiency, shorten the reaction time due to large interface area and short molecule diffusion distance. At the end of reaction, Janus nanoparticles can be recovered by simple centrifugation, the relative activity of lipase remained 72.89% after repeated use for 6 times. Overall, this paper provides a high efficiency, sustainability interfacial biocatalysis technique for synthesis phytosteryl oleate.