Abstract
Objective: Demand for new antibiotic is rising up due to continuous resistance risk against conventional antibiotic. This attempt was taken to find out a novel antimicrobial metabolite.
Methods: Chili field antagonistic actinomycetes Streptomyces albolongus was isolated and tested for optimum antimi¬crobial metabolite production. Primary screening was done by selective media and antibiotic assay was done by agar cup plate method. Fermented product was recovered by separating funnel using suitable solvent.
Results: Maximum antimicrobial metabolite production was found at temperature 35°C and pH 9.0 and on 6th day of incubation. The medium consisting of corn steep liquor (0.2%), glucose (1.0%), NaCl (0.5%), K2HPO4 (0.1%) was screened out as suitable medium for maximum antimicrobial production. Sucrose was found as the best carbon source among four sources. The antimicrobial metabolite was found to be stable at pH and temperature up to 11.0 and 100°C respec¬tively. The active agent was best extracted with chloroform. The antimicrobial spectrum of the metabolite was wide and shows activity against Shigella dysenteriae (AE14612), Shigella sonnei (CRL, ICDDR, B), Salmonella typhi (AE14296), Vibrio cholerae (AE14748), Pseudomonas aeruginosa (CRL, ICDDR, B), Bacillus cereus (BTCC19), Staphylococcus aureus (ATCC6538), Bacillus subtilis (BTTC17) and Bacillus megaterium (BTTC18).
Conclusion: The findings of antibacterial activity of S.albolongus against several species of human pathogens including both Gram-positive and Gram-negative bacteria indicated that our produced material might be an alternative antimicrobial substance to control human diseases. J Microbiol Infect Dis 2013; 3(2): 75-82

Key words: Streptomyces albolongus, antimicrobial metabolite, optimum production, antimicrobial spectrum