THE CARBOXYLATE TYPE SIDEROPHORE RHIZOFERRIN AND ITS ANALOGS PRODUCED BY DIRECTED FERMENTATION

Rhizoferrin is a novel carboxylate-type siderophore which has recently been isolated from Rhizopus microsporus and other fungi of the Mucorales (Zygomycetes). The present investigation shows that a variety of rhizoferrin analogs can be produced by directed fermentation. Thus both the diaminobutane backbone and the citric acid side chains of rhizoferrin have been substituted by diamine and citric acid analogs added to the culture medium. The new ligands as well as their iron complexes have been characterized by physicochemical methods. Conditions of precursor incorporation and implications for the biosynthesis of the new siderophores are discussed.