Extraction and Characterization of Antibiotic Compounds produced by Streptomyces spp. VITGV01 against Selected Human Pathogens

Abstract

\n Streptomyces are well known to produce a large number of diverse antibiotic compounds. New environments are being explored and some new Streptomyces strains have been discovered; the potential of the plant endophytic environments has been highly explored during the last decade. In the present study, an endophytic actinomycete, VITGV01, was isolated from a farm tomato plant collected from an agricultural field. These actinomycetes are cultured in ISP2 medium supplemented with nystatin (15µg/ml) and nalidixic acid (50µg/ml). Based on the 16S rRNA analysis and physiological tests, this isolate was found to be a member of the known genus Streptomyces spp. and suggesting that it might be a new spp. The isolated strain showed morphological and chemical characteristics of the genus Streptomyces. The strain VITGV01 produced different antibiotics on different media such as yeast extract, malt extract, glucose medium, which were active against some Gram-positive and negative bacteria [Bacillus subtilis (MTCC2756), Staphylococcus aureus (MTCC737), Escherichia coli – (MTCC1687), and Klebsiella pneumoniae (MTCC109)]. The primary and secondary screening was performed against these human pathogens. Maximum zone of inhibition was observed against K. pneumoniae (22 mm) and minimal zone of inhibition against B. subtilis (8 mm). Maximum biomass production was recorded in media containing 1% sucrose and 1% yeast extract cultured at pH 7.0 for 7 days at 30◦C. FTIR analysis revealed amine, alkane (C\u2009=\u2009C) of the aromatic ring, secondary alcohol, and alkyl halide groups. The GC–MS data showed twenty compounds, of which fifteen are antimicrobial compounds.