The Fluorescent Pigment of Pseudomonas fluorescens : Biosynthesis , Purification and Physicochemical Properties

The biosynthesis of a yellow-green, fluorescent, water-soluble pigment by Pseudomonas jluorescens occurred only when the bacteria were iron-deficient and was not directly influenced by the nature of the organic carbon source. The pigment formed a very stable Fe3+ complex and was purified in this form. Pseudomonasfluorescens produced only one molecular species of fluorescent pigment; however, its lability under mild alkaline conditions led to the formation of several pigmented decomposition products. The spectral properties of the pure pigment, its molecular weight (1500 rf: 75) and its stability constant for Fe3+ (of the order of were determined. Both its biosynthesis and its chemical properties (formation of a stable Fe3+ complex) suggest that the fluorescent pigment is a desferrisiderophore.