Hemolytic activity of Streptomyces VITSDK1 spp. isolated from marine sediments in Southern India

A moderately halophilic actinomycete strain was isolated from marine sediments collected at the Marakkanam coast of Tamil Nadu, India. The taxonomic position was evaluated by polyphasic approach and the strain was identified as a member of the genus Streptomyces. The strain is congruent with the description of the genus Streptomyces due to the characteristics of white aerial cell mass, spiral spore chains and a rough spore surface, menaquinones of MK-9 (H-4, H-2 and H-6) types and belongs to cell-wall type I. The G + C content of the isolated DNA is 71.3 mol% and the 16S rRNA sequence of the strain shows a maximum of 93% similarity with Streptomyces HBUM 49447. The comparison of phenotypic data of closest strains with the isolate clearly indicates that our strain belongs to the genus Streptomyces. Based on the phenotypic and phylogenetic analysis, the strain was classified as a new species of the genus Streptomyces and designated as VITSDK1. The media and cultural conditions for maximal growth have been optimized under shake-flask conditions by measuring the dry weight of the mycelium. The maximal growth was attained with the use of optimized production medium, pH of 7.2 and incubation temperature of 27 degrees C. The growth of the strain was salt concentration dependent and maximal growth was attained at 15% salt concentration which indicates the halophilic nature of the isolate. Streptomyces VITSDK1 spp. exhibits significant hemolytic activity against rat erythrocytes with the EC50 value of 127 mu g/ml and for human erythrocytes 168 mu g/ml. Further, it shows moderate antibiosis against fungi and bacterial. pathogens. (c) 2009 Elsevier Masson SAS. All rights reserved.