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Please use this identifier to cite or link to this item: http://hdl.handle.net/10204/1381

Title: Optimisation of the enantioselective biocatalytic hydrolysis of naproxen ethyl ester using ChiroCLEC-CR
Authors: Brady, D
Steenkamp, L
Skein, E
Chaplin, JA
Reddy, S
Keywords: Candida rugosa lipase
Naproxen ester
Applied microbiology
Issue Date: 4-Mar-2004
Publisher: Elsevier Science Inc.
Citation: Brady, D et al. 2004. Optimisation of the enantioselective biocatalytic hydrolysis of naproxen ethyl ester using ChiroCLEC-CR. Enzyme and microbial technology, vol 34, 4 March, pp 283-291
Abstract: In a biocatalytic reaction the immobilized lipase ChiroCLEC-CR enantioselectively hydrolysed a naproxen ethyl ester racemate, yielding (S)-naproxen with an enantiomeric excess of more than 98%, an enantiomeric ratio (E) of more than 100, and substrate conversion in excess of 40%. Statistically designed experiments were performed to optimise temperature, enzyme to substrate ratio, substrate concentration, agitation, reaction time, pH, buffer concentration and co-solvent addition. Optimisation efforts resulted in more than 20-fold improvement of activity, while the excellent enantioselectivity of the enzymes was maintained. In particular, the addition of PEG 1000 as a co-solvent improved conversion rates 10-fold. The kinetic parameters V-max and K-M were determined to be 0.359_mol/min/mg and 17.6 mM, respectively. The optimised reaction conditions were 10% (m/v) substrate, and enzyme to substrate ratio of 1:50, at 50 degrees C and pH 5 with addition of 41% PEG 1000. In spite of these kinetic improvements, the stability of the biocatalytic activity under these conditions was poor, limiting the number of possible recycles.
URI: http://hdl.handle.net/10204/1381
ISSN: 0141-0229
Appears in Collections:Microbial expression systems
Enzyme technologies
General science, engineering & technology

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