FLUORESCENCE OF AZOTOBACTER: I. A COMPARISON OF THE FLUORESCENT PIGMENTS WITH RIBOFLAVIN

Abstract

The fluorescent pigments elaborated in cultures of certain species of Azotobacter were compared with riboflavin produced by the same cultures. No correlation between the amounts of fluorescence and riboflavin was observed. Iron appears to inhibit the synthesis of the fluorescent pigments but stimulates riboflavin production. The fluorescent pigments obtained from Azotobacter were water-soluble, thermostable, insoluble in water-free organic solvents, and each exhibited a single absorption peak in the region of 370–380 mμ in slightly acid solution shifting to 400–420 in alkaline solution. Partial purification has been achieved by continuous paper electrophoresis with an acid electrolyte. These studies appear to indicate that the marked fluorescence observed in certain Azotobacter cultures cannot be attributed to riboflavin.