Studies on antifungal substances, phaefacin and moldin, produced by Streptomyces sp.

ptomyces. Thiolutin (aureothricin)9), an antibiotic produced by a new species of streptomyces, S. thioluteus, inhibits the growth of both bacteria and fungi. The writers' preliminary examination of various streptomyces indicated that S. griseus, S. aureofaciens, S. radiae, S. lavendulae, and several other strains produced substances inhibitorily effective to Candida albicans. Besides, two strains, one of which is resembling to S. phaeochromogenus, and another of which to a new species, were found to produce antifungal substances. The antifungal substance of the former is extracted with ethyl acetate and inhibits the growth of various fungi. Its effect to C. albicans is rather suppressive than f ungicidal and the inhibitory effect depends upon the period of incubation in the medium containing this substance. This substance seems to be new, and the writers named it •gMoldin•h. The latter seems to be a new sepcies and was named S. phaeofaciens, accordingly the antifungal substance •gPhaeof acin•h. The nature of the strains and the antifungal substances are reported in the present paper. Also their effects are shown with those of thiolutin and rimocidin.