Fig. 1

Pathways for fermentation of aromatic amino acids. Tyrosine (Tyr), phenylalanine (Phe), and tryptophan (Trp) are converted into cresol, toluene, and skatole, respectively. HPAD p-hydroxyphenylacetate decarboxylase, PhdB phenylacetate decarboxylase, and IAD indoleacetate decarboxylase