Abstracto

Streptomyces noursei var saccharicus: An Antibiotic Producer from Soils

P Ellaiah and VS Venkateswara Rao

During our continuous search for antibiotic producing actinomycetes, a variant of Streptomyces species was isolated from soils of Andhra Pradesh in India. The morphological, cultural, physiological and biochemical characters were studied, compared to known species and identified as a new variant of Streptomyces noursei and designated as Streptomyces noursei var saccharicus. The antibiotic activity of the strain was tested against both Gram-positive and Gram-negative bacteria as well as fungi and yeasts. INTRODUCTION Since the isolation of actinomycin in 1940 and streptomycin in 1944 by Waksman, the actinomycetes have received tremendous attention of the scientists. Soils, composts and fodders are common sources of actinomycetes. Waksman [1] recognized a few natural substrates as ideal sources for the isolation of actinomycetes and other streptomycetes. The nature of a Streptomyces colony is an important property in characterizing a culture. Krainsky [2] used the structure, size, shape and texture of the colony as one of the major diagnostic criteria. According to Pridham and Lyons [3] and International Subcommittee [4], the best way to handle streptomycete classification nomenclature and identification is through application of the genus-species-subspecies concept. The majority of antibiotic producing actinomycetes found in these species led to growing economic importance of these organisms which resulted in the isolation and description of numerous new species. It is reported that the only genus Streptomyces, the member of Actinomycetales accounts for approximately 93% producing secondary metabolites [5]. The present communication deals with the isolation and characterization of an antibiotic producer from soils.