Enzymatic hydrolysis of racemic ibuprofen esters using Rhizomucor miehei lipase immobilized on different supports

This research describes the immobilization of Rhizomucor miehei lipase (RML) and chemically aminated RML (NH₂-RML) on different supports including octyl-sepharose (octyl-RML), activated sepharose with cyanogen bromide (CNBr-RML and CNBr-NH₂-RML), glyoxyl sepharose (Gx-RML and Gx-NH₂-RML) and glyoxyl sepharose dithiothreitol (Gx-DTT-RML and Gx-DTT-NH₂-RML). The highest immobilization yield was achieved for octyl-RML (>98%) followed by CNBr-RML (88%). Octyl-RML had the most specific activity (13.6) among all derivatives. The other preparations had moderate activities likely because of chemical reaction during covalent attachment of the enzyme. The catalytic behavior of lipase immobilized in hydrolysis reactions was investigated using methyl, ethyl, propyl, butyl and isobutyl-ibuprofen esters and the influence of the alkyl chain and the alcoholic residue of the ester were studied. Butyl ester was the most interesting ester for carrying out hydrolysis. The highest enantioselectivity of enzyme (E = 8.8) was obtained with isooctane/sodium phosphate buffer pH 7.0 at temperature of 40 °C. Increasing temperature from 40 to 50 °C caused decreasing in enantioselectivities and conversions. Also esterification of ibuprofen was carried out in solvent systems containing isooctane and two ionic liquids (ILs); BMIM]PF₆] and BMIM]BF₄]. Poor conversions and enantioselectivities were observed during esterification in all solvents.