Selective Oxidation of α,β-Unsaturated Alcohols with Lyophilisates of Bjerkandera adusta

The biocatalytic aerobic production of (E)-2-allylic aldehydes from their corresponding alcohols using lyophilisates of the basidiomycetous fungus Bjerkandera adusta is reported. The addition of small amounts of organic solvents to the reaction media increased the reaction and substrate conversion rates, allowing for to produce (E)-aldehydes under sustainable conditions. Citral (mixture of (E)- and (Z)-3,7-dimethylocta-2,6-dienal) was found as a result of the oxidation of geraniol ((E)-3,7-dimethyl-2,6-octadien-1-ol) as well as of nerol ((Z)-3,7-dimethyl-2,6-octadien-1-ol). In the case of (Z)-2-nonene-1-ol, the formation of (E)-2-nonenal was detected as the only product. The isomerization of (Z)-2-nonenal to the corresponding (E)-diastereomer with fungal lyophilisate under the applied reaction conditions has been shown in additional experiments. No products of further oxidation of the formed aldehydes or reduction of the activated CC-double bond were detected in the reaction mixtures. A comparative analysis of the catalytic activity of lyophilisates obtained from Pleurotus sapidus and Pleurotus eryngii, as well-known producers of oxidative enzymes, was performed in model experiments.