From Pseudomonas sp. CFML 95-275 a pyoverdin was isolated with a cyclopepti
dic substructure. it could be shown that this pyoverdin is identical with o
ne obtained from Pseudomonas fluorescens BTP 7 for which a lactone structur
e had been deduced from the interpretation of a FAB spectrum. The elucidati
on of the correct structure of the pyoverdin is described.