Isolation and structure of a new phenoxazine antibiotic, exfoliazone, produced by Streptomyces exfoliatus.

containing 30 liters of a medium with agitation rate of 400rpm and air flow of 30 liters/minute. The medium consisted of glucose 2.5%, soybean meal 1.5% dry yeast 0.2% and CaCO3 0.4%; pH was adjusted to 6.2. After fermentation for 90 hours, the culture broth was separated into filtrate and mycelium by centrifugation. The flow diagram for the isolation of I is shown in Fig. 1. The culture filtrate was adsorbed on Diaion HP-20 (10 liters, batch treatment), which was washed with water and then eluted with MeOH. The active eluate was concentrated under reduced pressure to 5 liters and the aqueous residue was extracted with CHC13.