Taxonomy and Antimicrobial Activity of Streptomyces coeruleorubidus sp. Isolated from Marine Sediment

A new isolate of actinomycete has been isolated from marine sediment sample collected from Bay of Bengal near Visakhapatnani coast, as a result of screening actinomycete isolates producing antimicrobial compounds. The isolate exhibited broad spectrum of antimicrobial activity against the pathogenic bacteria and fungi used in the study. The isolate exhibited bluish green to light blue aerial mycelium with long spore chains which are non-motile spores with spiny surfaces. Growth of the isolate occurred in 2-7% (w/v) NaCl at pH 5.2-10.0 and at 25-42C. The predominant menaquinones are MK-9 (H6) (81%) and MK-9 (H8) (19%) and the major cellular fatty acids were anteiso-C15.0, iso-C16.0 and iso-C15.0. The DNA G+C content of the strain was 64.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain belongs to genus Streptomyces, with highest similarity to Streptomyces coeruleorubidus NBRC 12844T (99.5%). Based on the physiological, biochemical and chemotaxonomic tests, the actinomycete was identified as an isolate of Streptomyces coeruleorubidus sp. from marine sediment.