The role of the reaction medium in lipase-catalyzed esterifications and transesterifications

The nature of the reaction medium (different organic solvents and supercritical fluids) markedly influenced the microbial lipase activity in esterification and transesterification reactions employing as substrates natural and synthetic compounds in terms of reaction rates and lipase enantioselectivity. The experimental data obtained show that while there are no substantial correlations between enantioselectivity and some physicochemical characteristics of the solvent as hydrophobicity and dielectric constant, the solvent polarity and hydrophobicity is able to modulate greatly lipase activity. The possible effects of the solvent characteristics on the catalytic performance of the enzymes are discussed and a rationale is proposed to explain the results obtained. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.