Enzymatic Synthesis Of Biotin Intermediate Chiral Lactone And The Resolution Of Naproxen

Biotin is an important vitamin which is essential to the normal physiological activities of animals and human life. This thesis studies the biocatalytic synthesis of important intermediate of chiral lactone of (+)-biotin. First we screened a micro-bacterium which can selectively hydrolyze the substrate of diester. Then we studied the reaction conditions which can affect the enzyme activity, including substrate concentration, pH, temperature, organic solvents, dispersants, additives, etc. Experimental results show that the enzyme-catalyzed hydrolysis process shows high conversion rate when the substrate concentration is 10 mg/mL and pH value is 7.5. The reaction is positively correlated with temperature and the conversion has reached 90% when the temperature is 40℃. The additives of polyethylene glycol (6000) and P-cyclodextrin can efficiently improve the conversion. The conversion is increased by 40 percent by addingβ-cyclodextrin into the reaction system compared with that withoutβ-cyclodextrin. The e.e. value of chiral lactone obtained by enzyme catalysis is 97.9%, the same as the standard industrial sample. And the specific rotation of biotin lactone is +60.5℃.The second part of the thesis examined how to isolate an important raw material of alkanolamine from the waste water of (+)-biotin production. Among the tried methods, the one which extract the alkanolamine with ethyl acetate, then wash the crude alkanolamine with mixture solvent of methanol and methylene chloride is the most successful method. The recovery yield and purity are much higher than other methods.The third part of the thesis studies the resolution of racemic naproxen by an immobilized lipase. In a trapped aqueous-organic biphasic system, lipase from Candida rogusa is effectively immobilized on MCM-41 mesoporous molecular sieve. The immobilization efficiency is 100%. Under the same condition, the immobilized enzyme activity increase 5-fold compared with the free enzyme. After 12 days (three batchs), the remaining activity is 69%.