The heterologous expression of tryptophan trytophylquinone (TTQ)-dependent aromatic amine dehydrogenase (AADH) has been achieved in Paracoccus denitrificans. The aauBEDAgenes andorf-2from the aromatic amine utilization (aau) gene cluster of Alcaligenes faecaliswere placed under the regulatory control of themauFpromoter fromP. denitrificans and introduced intoP. denitrificansusing a broad-host-range vector.