Process for preparation of antibiotics and biologically pure culture for use therein

摘要

An antibiotic substance KA-7038 selected from the group consisting of the compounds having formulae I to VII described in claim 1, mixtures thereof and acid addition salts thereof; an antibiotic composition composed of (i) antibiotically effective amount of aforesaid antibiotic substance KA-7038, and (ii) a pharmaceutically acceptable diluent or carrier. The antibiotic substance KA-7038 can be produced by cultivating an antibiotic substance KA-7038-producing strain belonging to genus Streptomyces, for example Streptomyces sp. KC-7038, and isolating the antibiotic substance KA-7038 from the culture broth.