Process for preparing narasin

DETAILED DESCRIPTION The new microorganism of this invention is a biologically pure culture derived from a soil sample collected near the Surinam River, Surinam, South America.
The culture was given the number A-39912 for identification purposes.
Culture A-39912 is classified as Streptomyces granuloruber, based upon a simultaneous culturing of Streptomyces rubra; Streptomyces griseoruber; and Streptomyces griseoaurantiacus, using the methods and media recommended by Shirling and Gottlieb ["Methods of Characterization of Streptomyces species," Int.
Bull.
of Systematic Bacteriol.
16, 313-340 (1966)], along with certain supplementary tests.
Culture A-39912 was also compared with the description of Streptomyces longispororuber reported by Gerber, J.
Antibiot.
28, 194-199 (1975).
Culture A-39912 differs from Streptomyces rubra by producing granules, that is, crystals of undecylprodiginine, a purplish-red dye, by producing a purplish-red to black vegetative mycelium, and by reducing nitrate.
Culture A-39912 produces a red and gray aerial mycelium in contrast to the gray aerial mycelium of Streptomyces griseoruber.
The purplish-red to black vegetative mycelium produced by culture A-39912 also differs from the yellow brown to reddish orange vegetative mycelium of Streptomyces griseoruber.
Streptomyces griseoaurantiacus does not produce the distinctive purplish-red to black vegetative mycelium, as does culture A-39912.
Neither Streptomyces griseoruber nor Streptomyces griseoaurantiacus produces the purplish-red crystals of undecylprodiginine as does A-39912.
Thus, comparison of culture A-39912 with the above-named cultures shows significant differences.
Our culture is considered to be a new species and is described as Streptomyces granuloruber.
CHARACTERIZATION OF NARASIN-PRODUCING STRAIN Morphology Produces spiralled sporophores.
The spores are smooth as determined by electron microscopy and are oval to slightly cylindrical in shape.
The spores measure an average of 1.
3 .
mu.
m.
times.
2.
015 .
mu.
m with a range of 1