Study On The Synthesis Of Novel Functional Magnetic Nanocarriers For Lipase Immobilization

Magnetic nanomaterials become a research focus in recent years and widely used in organic catalysis,biosynthesis,drug delivery,environmental improvement and data storage,because of their special magnetic behavior,high specific surface area,excellent chemical durability and good biocompatibility.Research and synthesis of functional novel magnetic nanomaterials for lipase immobilization,can solve the problems like hard recovery and hard reuse,and then two kinds of novel reactive magnetic carriers were designed and prepared,they were employed in immobilizing lipase.The main contents for this thesis are listed as follows.1.Solvothermal synthesis of polyethyleneimine(PEI)functionalized magnetic nanoparticles for lipase immobilization.Fe3O4 nanopaticles with water solubility were synthesized by solvothermal method.The Fe3O4 nanoparticles were modified by PEI and amino groups were introduced onto the surface of the Fe3O4.Lipase was covalently immobilized on the obtain particles using glutaraldehyde as a coupling agent.TEM?FT-IR?VSM?XRD and TGA were used to characterize the Fe3O4 magnetic nanoparticles.Magnetic nanoparticles with uniform sizes showed monodispersity and magnetic response.The properties of the immobilized enzymes were also studied.The immobilized lipases exhibited excellent thermal stability and reusability.The immobilized lipases could be reused 10 times with the activity remained above 60%.This study provided a green and economical method of lipse immobilization and expected to be widely applied in industrial production.2.Solvothermal synthesis of magnetite nanoparticles modified by bidentate enediol ligands for lipase immobilization.In present study,monodisperse magnetic nanoparticles with uniform sizes were prepared through solvothermal method.Dopamine(DA)and 3-(3,4-Dihydroxy-phenyl)-propionic acid(DHCA)as bidentate enediol ligands were covalently bound at the magnetic nanoparticles through a green approach.Porcine pancreas lipase and Candida rugosa lipase were covalently immobilized on the hydrophilic magnetic carriers,respectively.SEM,TEM,VSM,FT-IR,TGA methods were used for characterize the structure and properties of two magnetic carriers.The study of immobilized lipases properties was illustrated that the immobilized lipase had better resistance to pH and temperature inactivation in comparison to free lipase,the adaptive pH and temperature ranges of lipase were widened,and it exhibited good thennal stability and reusability.Furthermore,the magnetic microspheres show a superparamagnetic property,there are easy to be separate after reaction.