An isolated strain of Trichosporon species (DSMZ 11829) was capable of producing a novel membrane-bound, enantioselective ester hydrolase. Its application in the kinetic resolution of racemic methyl ester of 6-methoxy-alpha-methyl-2-naphthaleneacetic acid (naproxen) into (S)-(+)-naproxen (> 99% ee, E similar to 500) and acyloxy derivatives of 1-chloro-3-(1-naphthyloxy)-2-propanol into (R)-alcohol (> 99% ee, E similar to 550) have already been reported by us. The enzyme designated as TSL was extracted from the cells by toluenization and purified to homogeneity from cell free extract with 8.5% overall yield. The purified enzyme with a specific activity of 831 U/mg protein was achieved by column chromatography using DEAE-Sepharose, phenyl-Sepharose and Sephadex G-100 resins. The purified enzyme exhibited hydrolytic activity without any noticeable decrease in the rate of hydrolysis or its enantioselectivty in the resolution of racemic naproxen into (S)-(+)-naproxen or in the resolution of 1-chloro-3-(1-naphthyloxy)-2-propanol and 1-(6-methoxy-2-naphthyl)ethanol. Purified enzyme is a glycosylated monomer with a molecular weight of similar to 40 kD and isoelectric point (pI) similar to 4.1. TSL was maximally active at 30 degrees C and pH 8.0. The enzyme was insensitive to serine reactive agent PMSF, metal chealator EDTA, non-ionic detergent Triton X-100 and reducing agent mercaptoethanol. The N-terminal amino acid sequence of TSL determined as Thr-Val-Thr-Thr-Pro-Thr-Leu-Ser-Ala-Asp-Ala-Lys-Lys-Gly- did not reveal any homology with the N-terminal amino acid sequence of any other known microbial ester hydrolases. (c) 2005 Elsevier Inc. All rights reserved.