Preparation Of Novel Hierarchical Porous Polymers And Catalytic Performance For Immobilized Phospholipase

Hierarchical porous polymer materials show great application prospects in the immobilization of enzymes due to their unique physical and chemical properties,large specific surface area and adjustable mesoporous structure.Hierarchical porous polymer has multi-scale pores,mesopores can achieve effective immobilization of enzyme molecules,and macropores can provide channels for rapid mass transfer,which can significantly improve the immobilization efficiency of enzyme molecules and biocatalysis of immobilized enzymes active.This paper has invented a new method for preparing hierarchical porous polymer aerogels,which requires no template,is simple and fast,and explores its application research in enzyme immobilization,and launch the following research work:(1)Preparation of epoxy resin-based hierarchical porous polymerWithout using a template,only one crystalline compound is used as the only dispersion system and porogen,and the combination of polymerization induction and rapid freezing induction is used to achieve the simultaneous formation of mesopores and macropores and ultra-large pores.After the completion of the polymerization reaction,the water-soluble compound is removed by a simple environmentally friendly treatment method of immersion in water,and dried at normal temperature and pressure to obtain a large-sized hierarchical porous polymer with 3D penetration,good hole wall continuity and good mechanical stability.Its pore size ranges from 50?m to 10 nm.The porosity and specific surface area of?? the hierarchical porous polymer can reach 91.2-82.5%and 225-156 m²/g,respectively.Because of its high specific surface area,ordered pore structure,diverse pore size,and good thermal stability,it can be used as a place for biological macromolecules to catalyze reactions.(2)Catalytic performance of epoxy resin-based hierarchical porous polymer immobilized phospholipase DPhospholipase D(PLD)was effectively immobilized by using a hierarchical porous polymer as a carrier through physical adsorption.Due to the high porosity and increased mass transfer rate of the carrier,the loading of PLD is as high as 223 mg/g_support,and the corresponding specific activity is as high as 3.75×10³U/g_support.Under optimal conditions,the yield of phosphatidylserine(PS)reached 95.5%in 40 minutes at 45?.Immobilized PLD not only showed better storage stability than free PLD,but also had p H stability and resistance The ability to heat inactivate.After12 repeated uses,the retained PS yield was 73.5%.(3)Catalytic performance of epoxy resin-based multistage porous polymer immobilized phospholipase A₁In order to further study the catalytic performance of the prepared hierarchical porous polymer material when immobilizing other phospholipases,the phospholipase A₁(PLA₁)was immobilized on the hierarchical porous polymer by physical adsorption.The results show that the loading capacity and specific activity of PLA₁are up to 188 mg/g_supportand 3550 U/g_support,respectively.Under the best conditions,30 mg immobilized PLA₁,substrate mass ratio(PC/ethyl ester)=1:6,reaction temperature 50?,water addition 0.75%(relative to the total substrate mass)and react for13 hours.At this time,the total substitution rate of docosahexaenoic acid(DHA)/eicosapentaenoic acid(EPA)reached 53.7 mol%,and the yield of phosphatidylcholine(PC)was 65.8%.Immobilized PLA₁has good reusability,and retains 85.2%activity after 12 cycles of repeated use.