Studies on the Antibiotic Producing Actinomycetes II : On the Identification, Culture Condition and Antibiotic Substance of F 1001 Strain

Among numerous Streptomyces-strains isolated from soils, F 1001, so-called in our laboratory, exhibited the widest inhibition zone against pathogenic bacteria in the course of our screening-tests. The fact suggests that this strain has an ability to produce the antibiotic in a large amount. Spirals are formed at the ends of hyphae only on the agarmedia extremely poor in nutrients. The hyphae excrete brown pigments that diffuse into the media, when a protein component such as meat extract or peptone is added. From this the strain seems to be of Chromogenus type. Judging from several taxonomic characteristics, we have identified it as one strain of Streptomyces aureus (Waksman and Curtius) group. Cultivation of the strain on 6 kinds of media of different compositions showed the glucose bouillon medium, rendered semicolloidal by adding 0.25% agar, as most suitable for the production of antibiotics. Optimum pH of the broth for growth as well as for potency is 7.0, and optimum temperature for growth is 24℃, while that for potency is 30℃. Broth filtrates inhibit the growth of Staph. aureus in about 20,000,000 dilution, E scher. coli in about 200,000 dilution. Next we tried to extract active substances out of broth by the usual method and have got a white powder with pale yellowish brown tincture. As a solvent for elution of active substances from charcoal, methanol acidified by hydrochloric acid (pH 2) is excellent, and methanol acidified by sulfuric acid (same pH) falls behind. The powder gives brown colored Sakaguchi-reaction, and forms crystalline reineckate as well as helianthate. It is able to inhibit the growth of all the three groups of pathogenic bacteria i.e., Gram positive, Gram negative and acid-fast bacteria (Mycobacterium tuberculosis bovine type). Lytic action upon bacterial bodies is not so conspicuous. Concerning heat stability, it is indifferent to 3-minute heating at 100℃, while the potency decreases considerably by 5-minute heating at 100℃