[Utilization by Escherichia coli and Pseudomonas fluorescens of a siderophore from Pseudomonas fluorescens strain PAB].

Pseudomonas fluorescens PAB strain produced pyoverdine in a synthetic medium. Pigment was purified by solvent extraction and ion exchange, and sterilized and used as siderophore for E. coli, P. fluorescens, ATCC 13.525, ATCC 17.400, W and PAB strains. Bacteria were grown in iron-free medium and medium with iron. Free--pyoverdine and pyoverdine bound to Fe+3 were added in different concentrations. P. fluorescens PAB siderophore did not stimulate E. coli growth while it was selective for other P. fluorescens strains. Paper disks impregnated with pyoverdine did not inhibit E. coli growth.