SO-75R1, a new mutactimycin derivative produced by Nocardia brasiliensis.

In the course of studies on biologically active substances from pathogenic microorganisms, a new antibiotic SO-75R1 was isolated from the mycelium of Nocardia brasiliensis IFM 075. This paper describes the fermentation, isolation and structural elucidation of SO-75R1. The seed broth was prepared by inoculating mycelial elements of the producing strain (IFM 075) grown on Sabouraud dextrose agar (Difco) into 10ml brain heart infusion broth with 2% glucose in 50-ml Erlenmeyer shake flasks. The culture was