Caulobacter segnis dioxygenase CsO2: a practical biocatalyst for stilbenoid ozonolysis

Ozonolysis is a useful as well as dangerous reaction for performing alkene cleavage. On the other hand, enzymes are considered a more sustainable and safer alternative. Among them, Caulobacter segnis dioxygenase (CsO2) known so far for its ability to catalyze the coenzyme-free oxidation of vinylguaiacol into vanillin, was selected and its substrate scope evaluated towards diverse natural and synthetic stilbenoids. Under optimized conditions, CsO2 catalyzed the oxidative cleavage of the C=C double bonds of various trans-stilbenes, providing that a hydroxyl moiety was necessary in para-position of the phenyl group (e.g., resveratrol and its derivatives) for the reaction to take place, which was confirmed by modelling studies. The reactions occurred rapidly (0.5-3 h) with high conversions (95-99%) and without formation of by-products. The resveratrol biotransformation was carried out on 50-mL scale thus confirming the feasibility of the biocatalytic system as a preparative method.