4-EP is biosynthesized in two steps from p-coumaric acid. Decarboxylation gives 4-vinylphenol as catalyzed by the enzyme cinnamate decarboxylase.Brettanomyces Monitoring by Analysis of 4-ethylphenol and 4-ethylguaiacol at etslabs.com 4-Vinylphenol is further reduced to 4-ethylphenol by the enzyme vinyl phenol reductase. Coumaric acid is sometimes added to microbiological media, enabling the positive identification of Brettanomyces by smell.
