Propyl-glycoside lactate, a new alpha-hydroxy acids derivative, was synthesized by esterification between lactic acid and propyl-glycoside, instead of transesterification as reported previously, in a non-aqueous medium using immobilized lipase as biocatalyst. A conversion of 66% was achieved by the optimization of the reaction conditions. Lipase activity was found to be reduced when exposed to high concentration of glycoside. Presence of silica gel in reaction medium improved conversion and initial rate significantly without altering the kinetic mechanism of the enzymatic esterification reaction. Addition of molecular sieves eliminated hydrolysis of the produced ester and allowed glycoside conversion rising to 75%. (C) 2003 Elsevier Inc. All rights reserved.