Efficient Production of Diltiazem Chiral Intermediate using Immobilized Lipase from Serratia marcescens

The lipase from Serratia inarcescence ECU1010 (SmI) was capable of enantioselectively catalyzing the synthesis of many chiral drug precursors. This paper investigated the immobilization of Sml on appropriate supporting materials and its performance in bioreactor. Chitosan, Celite 545, and DEAE-cellulose were found to be the ideal supports among 8 carriers tested with respect to enzyme load and activity recovery of lipase. When Sml was immobilized, significant improvements of stability against pH, thermal, and operational deactivation were observed with all the 3 better supports, and the best stability was observed when the lipase was immobilized on glutaraldehyde activated chitosan. As for the effect of organic solvent in the biphasic reaction system, the hydrolytic activity of the immobilized lipase on trans-3-(4'methoxyphenyl)glycidic acid methyl ester ((+/-)-MPGM) observed in isopropyl ether was 6 and 3 times higher than those in toluene and methyl tert-butyl ether. The lipase-catalyzed production of ()-MPGM by enzymatic resolution of (+/-)-MPGM with chitosan-Sml in isopropyl ether-water biphasic system was carried out in a 2 L stirred-tank reactor. The batch operation was more efficient operation mode for the enantioselective hydrolysis of (+/-)-MPGM, affording enantiopure (+/-)-MPGM in 44.3% overall yield, in contrast to 29.3% in a continuous reactor.