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Please use this identifier to cite or link to this item: http://hdl.handle.net/10204/5641

Title: Biocatalytic enantiomeric resolution of l-menthol from an eight isomeric menthol mixture
Authors: Brady, D
Reddy, S
Mboniswa, B
Steenkamp, LH
Rousseau, A
Parkinson, CJ
Chaplin, J
Mitra, RK
Moutlana, T
Marais, SF
Gardiner, NS
Keywords: Transesterification
Lipases
BSTR
Pseudomonas fluorescens
Diasteromeric
Enantiomeric resolution
Issue Date: Mar-2012
Publisher: Elsevier
Citation: Brady, D, Reddy, S, Mboniswa, B, Steenkamp, LH, Rousseau, A, Parkinson, CJ, Chaplin, J, Mitra, RK, Moutlana, T, Marais, SF and Gardiner, NS. 2012. Biocatalytic enantiomeric resolution of l-menthol from an eight isomeric menthol mixture. Journal of Molecular Catalysis B, vol. 75, pp 1-10
Series/Report no.: Workflow;5992
Abstract: The four diastereomers of menthol and their enantiomers, namely dl-menthol, dl-neomenthol, dl-neoisomenthol and dl isomenthol, were synthesised by the hydrogenation of thymol to yield an eight isomer liquid menthol. A suitably selective lipase was sought to preferentially esterify l-menthol in hexane, hence simplifying separation from this diasteromeric mix through distillation. From an initial screen of over 70 enzyme preparations, a commercial Pseudomonas fluorescens lipase (Amano AK) was selected, and vinyl acetate was chosen as a suitable irreversible acyl donor for transesterification. The enzyme was recycled a total of 150 times in 5 ml batch reactions using liquid menthol and achieving an overall yield of 184.31 g dl-menthol/g enzyme. An enantiomeric excess of l-menthol of greater than 95% was reproducibly achievable at a conversion of 30% dl-menthol (0.68 M) at =50°C. On the basis of the composition of liquid menthol the reaction had a diastereomeric ratio of 81%. The resolution reaction was scaled up 400 fold to 2 L and the ezyme recycled 38 times with an average conversion of the available l-menthol of 59%.
Description: Copyright: 2012 Elsevier. This is the post-print version of the work. The definitive version is published in Journal of Molecular Catalysis B, vol. 75, pp 1-10
URI: http://www.sciencedirect.com/science/article/pii/S1381117711002797
http://hdl.handle.net/10204/5641
ISSN: 1381-1177
Appears in Collections:Enzyme technologies
General science, engineering & technology

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