Biocatalytic aldehyde reduction using tailor‐made whole‐cell catalysts: a novel synthesis of the aroma chemical cinnamyl alcohol

A biocatalytic method for the synthesis of the aroma chemical cinnamyl alcohol by means of a wholecell‐catalysed reduction of cinnamyl aldehyde has been developed. As a biocatalyst, recombinant whole cells overexpressing an alcohol dehydrogenase from Lactobacillus kefir and a glucose dehydrogenase from Thermoplasma acidophilum have been used in combination with d‐ glucose as co‐substrate. The reduction process proceeds with a conversion of 98%, even at a high substrate input of 166 g/l cinnamyl aldehyde, and gives a yield of 77% of the desired product, cinnamyl alcohol. In addition to high product concentrations, further advantages of this approach are the use of a low‐cost whole‐cell catalyst, the high purity of the product, as well as the fact that there is no need for the addition of external co‐factor in the biotransformation step. Copyright © 2007 John Wiley & Sons, Ltd.