The description and antibiotic production of Streptomyces hygroscopicus var. Geldanus

A new variety of Streptomyces hygroscopicus was isolated from a Kalamazoo soil. This isolate is described and identified as var. geldanus. When fermented in preferential media it produces geldanamycin, nigericin, nocardamine, and a libanamycin-like activity. Fermentation conditions, chromatographic separation, and antimicrobial spectra of the antibiotics are given.