Biologie moléculaire : accès libre

Studies on Antibacterial Activity of a Cyanobacterium Tolypothrix fragilis (Gardner) Geitler

Abstract

Janardhan Namdeo Nehul

Tolypothrix fragilis, a cyanobacterium was isolated from the collected soil samples from different locations of Ahmednagar district of Maharashtra state (India). Identification was carried out using morphological variation and taxonomical approaches according to Desikachary and Prescott. The axenic culture of Tolypothrix fragilis was obtained by using the method recommended by Bolch and Blackburn. The isolated Tolypothrix fragilis was grown autotropically in BG-11 medium and incubated at 30 ± 2°C. After 25 days, biomass was harvested by filtration through double layered muslin cloth and dried using air blower. The biomass of this Tolypothrix fragilis species was used for the assessment of antibacterial activity against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Micrococcus flavus and Proteus mirabilis. The antibacterial activity was studied by disc diffusion method. Methanol extract of Tolypothrix fragilis showed the activity against all the tested bacterial strains. Maximum zone of inhibition (22 ± 1.4 mm) was recorded with methanol extract of Tolypothrix fragilis against Bacillus subtilis. The MIC for all the bacteria was in the range of 32 – 256 μg/ml