A new actinomycin complex produced by a Micromonospora species: fermentation, isolation, and characterization.

A species of Micromonospora, Micromonospora floridensis NRRL 8020, has been found to produce an actinomycin complex consisting of at least 25 active components. After solvent extraction of the complex, separation of the individual components was carried out by preparative thin-layer chromatography. Hydrolysis and subsequent electrophoretic and chromatographic identification of the amino acid content of each of the isolated components have shown differences from known actinomycins, and the probability exists that these contain a number of amino or imino acids not previously found in other members of this group of antibiotics.

Binding of gentamicin and other aminoglycoside antibiotics to mycelium of various actinomycetes.

Gentamicin, an aminoglycoside antibiotic, occurs both free in the fermentation filtrate and bound to the mycelium of the producing organism, Micromonospora purpurea. The bound gentamicin, which represents the major portion of the total quantity present in the fermentation broth, was released after exposure to acid, alkali, or sonic disruption. Washing the mycelium with distilled water, heat treatment, and the addition of sodium chloride to the fermentation medium were not effective methods for releasing bound gentamicin. Gentamicin and other aminoglycoside antibiotics were effectively adsorbed from neutral aqueous solutions by the acid-extracted mycelium of M. purpurea. In addition, the acid-extracted mycelium of actinomycetes other than M. purpurea were shown to be able to adsorb gentamicin from solution.