new actinomycete strain designated Sg 10, producing antimicrobial substances was
isolated from an Algerian soil. Morphological and chemical studies indicated that
strain Sg 10 belonged to the genus Streptosporangium. The comparison of its
physiological characteristics with those of known species of Streptosporangium
showed significant differences with the nearest species Streptosporangium carneum.
Analysis of the 16S rDNA sequence of strain Sg 10 showed a similarity level ranging
between 96.3% and 97.8% within Streptosporangium species, with S. carneum the
most closely related. However, the phylogenetic analysis indicated that strain Sg 10
represent a distinct phyletic line suggesting a new genomic species. The
antimicrobial activity of strain Sg 10 showed an antibacterial activity against
Gram-positive bacteria as well as an antifungal one. Four active products were
isolated from the culture broth using various separation procedures. On the basis of
UV-VIS spectrometry, infrared spectroscopy and chemical revelations, the antibiotics
were classified in the group of glycosylated aromatics.
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