Esterase From Bacillus Megaterium Strain Used To Prepara Intermadiate Of Penem Drugs

penem is a kind of antibiotics that up to now has the broadest antibacterial spectrum and good antibacterial activity and as a result the use of penem drugs is on the increase at home and abroad. The current listing of penem drugs are imipenem, panipenem betamipron, faropenem, doripenem etc.Through the different gas chromatographic conditions, we established the chiral gas chromatography analysis method of methyl ester, methyl-2-tetrahydrofuroate, ethy-3-hydroxybutyrate acid, and ethyl lactate.This research screened a microbial strain from the lab-stored strains that has a fairly good stereoselective hydrolyzing activity towards (R,S)-methyl-2-tetrahydrofuroate and ethyl-3-hydroxybutyrate. Methyl-2-tetrahydrofuroate can be used for producing side chain and intermediate for meropenem. Optically pure R-EHB can be used to synthesis of chiral drugs such as imipenem.The research has also focused on the study of the conditions of lipase-catalytic hydrolysis reaction of (R,S)-methyl-2-tetrahydrofuroate with Bacillus megaterium strain WZ009, and the optimal reaction conditions are as follows:the ionic concentration is0.75mol/1, pH=7.2, the substrate density0.1%, the cell concentration0.25g/10ml, the reaction time16h, the conversion rate61.07%and e.es99.64%. The final product (R)-methyl-2-tetrahydrofuroate extraction methods were studied, and was analyzed with nuclear magnetic and infrared equipments.The research has also focused on the study of the conditions of enzyme-catalytic hydrolysis reaction of3-EHB with Bacillus megaterium strain WZ009.The optimum reaction conditions of asymmetric hydrolysis reaction are as follows:the temperature is30℃, pH is7, the substrate concentation is1%and the cell concentation is0.25g/10ml. Under such conditions and with two hours of reaction, the conversion rate is55.5%, and the e.es value of R-ethyl-3-hydroxybutyrate is99.9%。The repeated use of lipase of Bacillus megaterium strain WZ009have proved that the strain has fairly good stability.To two kinds of imipenem drug intermediates, WZ009has high stereoselectivity and catalytic activity. It is a kind of high performance biological catalyst, and has certain stability. It has good prospects for industrial application.