<jats:title>Abstract</jats:title> <jats:p> From a genetically manipulated strain of Pseudomonas aeruginosa ATCC 15692 (PAO 1 strain) a compound named pseudoverdin, 3-formylamino-6,7-dihydroxycoumarin, was obtained which is related to the typical pyoverdin chromophore and thus allows to shed some light on the biogenesis of the latter.