PRODUCTION, PURIFICATION AND CHARACTERIZATION OF AN ANTIBACTERIAL COMPOUND FROM STREPTOMYCES GRISEUS TBG19NRA1 ISOLATED FROM THE FOREST SOILS OF THE WESTERN GHATS OF KERALA, INDIA

A new actinomycete strain designated TBG19NRA1, exhibiting antimicrobial activities against Gram-positive and Gram-negative bacteria, was isolated from forest soil of Neyyar Wild Life Sanctuary, Thiruvananthapuram, Kerala. Cultural characteristics strongly suggested that this isolate belongs to the genus Streptomyces. Polyphasic taxonomic studies including phylogenetic analysis based on 16S rDNA sequence suggests that the isolate is a strain of S. griseus. Studies on the effect of different nutritional compounds on antibiotic activity revealed that the highest antibacterial activity was obtained when 1% starch (w/v) was used as the sole carbon source along with mineral trace elements. Extraction and purification of TBG19NRA1 culture supernatant led to the isolation of a pure molecule with good antibacterial activity. The compound has been identified as the cyclic polyether lasalocid A on the basis IR, MS and 13C NMR data interpretation and comparison with reference data from literature.