Abstract

ISOLATION AND CHARACTERIZATION OF ACTINOMYCETES FROM PADDY SOIL AND EVALUATION OF THEIR ANTIMICROBIAL ACTIVITIES

B.Sreedevi, M.R Thanusree and J.Pramoda kumari*

Department of Microbiology, Sri Venkateswara University, Tirupati, A.P-517502, India.

Abstract

Microbial pathogens are developing resistance against existing antibiotics, stressing for the discovery of new therapeutic compounds. In the course of screening for new antibiotic-producing microorganisms, isolates showing antimicrobial activity were isolated from paddy soil samples from various habitats in pudipatla near Tirupati, Andhra Pradesh, India. Both modified agar-cross streak and agar-disc, well diffusion methods were used in the primary and secondary screens. Isolated strains were identified for their antibacterial activity, three isolates showed good result, they were evaluated for their inhibitory activity on 3 strains of microorganism (E. coli, B. subtilis and S. aureus). TLC was done on silica gel using 100% Acetone and Methanol (MeOH) in 3:2 ratio and direct bioautography has shown the presence of active substance, with Rf valves 4, 6 and 7for A1, A2 and A3 respectively. Antibacterial compounds were produced by submerged fermentation and activity of compounds were checked against bacterial culture by antibiogram analysis where intracellular and extracellular compounds showed positive result, compare to intracellular compounds, extracellular compounds was showing best result which was 0.8cm zone of inhibition against S. aureus.

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