M. Pätzold, B. O. Burek, A. Liese, J. Z. Bloh, D. Holtmann
Bioprocess and Biosystems Engineering, 42 (2019), 1385–1389, doi:10.1007/s00449-019-02125-6
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 puriication of bioproducts from DES reaction mixtures has not yet been suiciently 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 efective biocatalytic process development, even if the limiting substrate is converted completely. Both DES compounds acted as substrates and reaction solvent in the lipase-catalyzed esteriication to synthesize (−)-menthyl dodecanoate. The product (−)-menthyl dodecanoate ester was separated from the DES reaction mixture by a vacuum distillation step and a second esteriication reaction can be performed with the recovered (−)-menthol.