Enzymatic resolution of naproxen

Trichosporon sp. (TSL), a newly found strain isolated from a locally fermented cottage cheese has been found to be highly stereoselective in the resolution of (S)-(+)-naproxen (ee >99%, Esimilar to500) from the corresponding racemic methyl ester. The process of resolution using whole cells has been scaled up to multi-kg level. Optimization of experimental conditions including downstream processing at 80-100 g/L substrate concentration with >90% recovery has been achieved. Changes in the physical parameters such as the particle size of the substrate play an important role in the resolution kinetics. A new strain of Trichosporon sp. having high cell density in cultivation (>60 g dry cell mass L-1 in 14-16 h) is found to be sufficiently stable for two years in dry powder form at 5-8degreesC. The viability of the resolution process has been further improved by the development of a simple racemization process for the enriched (R)-(-)-ester. (C) 2003 Elsevier Ltd. All rights reserved.