| This thesis reviews resolution technologies for chiral drugs, magnetic materials for immobilized enzyme and immobilized enzyme for resolution the chiral drug of non-steroidal anti-inflammatory drugs. The chiral drugs would be obtained by using lipase to catalyze the asymmetric hydrolysis of ester substances. But there are two main problems should be to solve. First, the solubility of ester substances is pretty poor. It’s difficult to catalyze the esters in the water. On the other hand, the free enzymes are uneasy in the organic solution. In order to solve these problems, we put forward the research ideas. The soluble ester of ibuprofen was synthesized to increase the solubility in water. The technology of enzyme immobilization, which could permit enzyme reuse and improve the stability of enzymes, was developed to overcome those weaknesses of free enzymes. Thus, we prepared four kinds of magnetic supports for lipase immobilization and studied the properties of immobilized lipase. For further application, the immobilized lipases were catalyzing the asymmetric hydrolysis of the soluble ester of ibuprofen. The main content of this dissertation is list as follows:(1) Controllable fabrication of magnetite hollow nanospheres and petaloid nanospheres and application for lipase immobilizationMonodisperse hollow and petaloid nanospheres with magnetism were prepared via a hydrothermal reaction based on regulating the proportion of raw materials. To understand the formation mechanism of this process, the reaction conditions such as the concentration of capping agent (PVP), gas source and the reaction time were investigated. The main formation mechanism of nanospheres was proposed based on a gas-bubble-assisted Ostwald ripening process. These nanospheres were functionalized by aminopropyltriethoxysilane (APTS) and glutaraldehyde respectively and then applied them to immobilize Candida rugosa lipase (CRL). The immobilized lipase exhibited excellent temperature and pH endurance than that of the free ones. The immobilized lipase also displayed large immobilization capacities compared with the solid microspheres.(2) Preparation of magnetic Fe3O4@chitosan/SBA15 support and their application for lipase immobilizationMonodisperse magnetic nanospheres functioned by chitosan (Fe3O4@CS) were prepared via a hydrothermal reaction. The resultant Fe3O4@CS was activated with glutaraldehyde to form nanoscale supports. Lipase (CRL) was covalently immobilized on the resulted magnetic supports. The immobilization capacities of the Fe3O4@CS reached 98.5 mg/g. In order to increase the immobilization capacities, SBA-15, with large specific surface area and pore volume, was chosen to connect with magnetic supports. The immobilization capacities of the Fe3O4@CS/SBA15 obtained 128.9 mg/g. The immobilized lipase exhibited excellent temperature and pH endurance than that of the free ones. The immobilized lipase of Fe3O4@CS/SBA15 also displayed excellent immobilization capacities compared with the Fe3O4@CS.(3) The magnetic immobilized lipases were catalyzing the asymmetric hydrolysis of the soluble ester of ibuprofenThe water soluble ester of ibuprofen was synthesized by formaldehyde sodium bisulfite and ibuprofen. It was asymmetrically hydrolyzed to get (S)-ibuprofen in the same amount of protein on the magnetic supports which we prepared to immobilize lipase (CRL). The immobilize lipase of Fe3O4@CS has a better result than the other supports. In contrast with the poor soluble ester of ibuprofen, the water soluble ester of ibuprofen is much better than others. Effects of pH, reaction time, the concentration of substance, reuse time on the conversion and enantiomeric excess of product were also studied. |
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