Enzymatic synthesis of vanillin

Due to increasing interest in natural vanillin, two enzymatic routes for th e synthesis of vanillin were developed. The flavoprotein vanillyl alcohol o xidase (VAO) acts on a wide range of phenolic compounds and converts both c reosol and vanillylamine to vanillin with high yield. The VAO-mediated conv ersion of creosol proceeds via a two-step process in which the initially fo rmed vanillyl alcohol is further oxidized to vanillin. Catalysis is limited by the formation of an abortive complex between enzyme-bound flavin and cr eosol. Moreover, in the second step of the process, the conversion of vanil lyl alcohol is inhibited by the competitive binding of creosol. The VAO-cat alyzed conversion Of vanillylamine proceeds efficiently at alkaline pH valu es. Vanillylamine is initially converted to a vanillylimine intermediate pr oduct, which is hydrolyzed nonenzymatically to vanillin. This route to vani llin has biotechnological potential as the widely available principle of re d pepper, capsaicin, can be hydrolyzed enzymatically to vanillylamine.