Taxonomy of the antibiotic Bu-2313-producing organism. Microtetraspora caesia sp. nov.

An aerobic actinomycete strain isolated from an Indian soil sample and designated No. E864-61 was found to produce in submerged fermentation a new antibiotic complex, Bu-2313 (components A and B). Strain E864-61 forms single, pairs or chains of three to eight spores on the aerial mycelium and its aerial mass color is grayish blue-green. The cell wall of strain E864-61 contains meso-diaminopimelic acid and galactose. Strain E864-61 has been classified as a new species of the genus Microtetraspora and designated as Microtetraspora caesia sp. nov.