A41030, A COMPLEX OF NOVEL GLYCOPEPTIDE ANTIBIOTICS PRODUCED BY A STRAIN OF STREPTOMYCES VIRGINIAE: TAXONOMY AND FERMENTATION STUDIES

A41030 is a complex of novel glycopeptide antibiotics produced by a culture isolated from a soil. Taxonomic studies have identified the microorganism, NRRL 15156, as a strain of Streptomyces virginiae. The major factor, A41030A, and three of the six minor factors are unique among glycopeptides in that they are naturally occurring aglycones, containing no neutral or amino sugars. The A41030 that was not spontaneously released into the fermentation broth could be released from the biomass into aqueous media at pH 10.5. In contrast to the vancomycin and N-demethylvancomycin fermentations, A41030 biosynthesis was stimulated by enriching the medium with K2HPO4 at a level of 1mg/ml. Enrichment with putative precursors of the aglycone, however, did not increase the biosynthesis of A41030.