INTECIN   20395
INSTITUTO DE TECNOLOGIAS Y CIENCIAS DE LA INGENIERIA "HILARIO FERNANDEZ LONG"
Unidad Ejecutora - UE
artículos
Título:
Enantioselective esterification of ibuprofen with ethanol as reactant and solvent catalyzed by immobilized lipase: experimental and molecular modeling aspects
Autor/es:
M. L. FORESTI; M. GALLE; M.L. FERREIRA; L.E. BRIAND
Revista:
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
Editorial:
Wiley Interscience
Referencias:
Año: 2009 vol. 84 p. 1461 - 1473
ISSN:
0268-2575
Resumen:
In the last years enantioselective esterification of racemic ibuprofen performed in organic solvent media and catalyzed by lipases has been proposed as an effective way to increase the concentration of unesterified S-ibuprofen in the racemic mixture. In this contribution, a system free of organic solvent is proposed as a novel eco-friendly medium to perform the enantioselective enzymatic esterification of (R,S)-ibuprofen. Results showed that the reaction in excess of the esterifying alcohol in a system free of organic solvent is possible if the proper conditions are set. The effects of the amount of water present in the reaction medium, the volume of the alcohol used as acyl acceptor, the reaction temperature and the enzyme loading, were alternatively analyzed in terms of the conversion of ibuprofen towards the ester and the enantiomeric excess achieved. Alcohol concentration showed to be determinant for both biocatalyst activity and enantioselectivity. The initial water content of reaction medium also showed to be a key parameter in a compromise between biocatalyst hydration and ester hydrolysis. Experimental data are further analyzed considering the results of extensive molecular modeling calculations devoted to the study of the enantiopreference of lipase towards the (R) enantiomer of ibuprofen, and the formation of dead-end compounds between the enzyme and ethanol/water that may account for lipase inhibition at high concentrations of those compounds.