Production of erythromycin E by pathogenic Nocardia brasiliensis.

Since the discovery of erythromycin A (1; Fig. 1)1} more than 25 biosynthetic representatives of this family of 14-membered macrolide antibiotics have been reported. Most of erythromycins are produced by the genera Saccharopolyspora and Streptomyces but few by Nocardia strains2). Erythromycin E (2; Fig. 1) is distinguishable from all the other known macrolide antibiotics and other microbial metabolites by the presence of an ortho-carboxylic acid ester structure. This is supplied by the oxidized form of cladinose which is bonded vicinally to the 14-membered aglycone3).