Product recovery of an enzymatically synthesized (−)-menthol ester in a deep eutectic solvent

Journal
Bioprocess and biosystems engineering  
Volume
42
Issue
8
Start Page
1385
End Page
1389
Citation
Bioprocess and Biosystems Engineering 42 (8): 1385-1389 (2019-08-01)
Publisher DOI
10.1007/s00449-019-02125-6
Scopus ID
2-s2.0-85065590967
PubMed ID
31069512
Deep eutectic solvents (DESs) have gained increased attention as alternative reaction media for biocatalysis in recent years. There are many investigations on biotransformations in a variety of DESs, but the purification of bioproducts from DES reaction mixtures has not yet been sufficiently addressed. The present study demonstrates a product recovery strategy from a DES reaction medium composed of (−)-menthol and dodecanoic acid. Since the DES is not formed by equimolar amounts of the substrates, but the eutectic point occurs at a 3:1 molar ratio, product isolation is an important task for effective biocatalytic process development, even if the limiting substrate is converted completely. Both DES compounds acted as substrates and reaction solvent in the lipase-catalyzed esterification to synthesize (−)-menthyl dodecanoate. The product (−)-menthyl dodecanoate ester was separated from the DES reaction mixture by a vacuum distillation step and a second esterification reaction can be performed with the recovered (−)-menthol.
Subjects
Deep eutectic solvent
Downstream processing
Lipase
Menthol
Vacuum distillation