and maintained in BG-11 growth medium (pH 7) under
rotatory conditions and illuminated continuously at a light
intensity of 3500 LUX. At the stationary phase of growth
(23 days) the culture was harvested, spent medium was
collected after fi ltering the biomass. The collected biomass
was dried in a hot air oven at 60°C for 1h and then placed
in solvent leave the mixture for 5 hrs at room temperature
and sonicated for 10 min and then centrifuged at 4000
rpm for 10 min. After centrifugation supernatant was
collected in a preweighed test tube then concentrated
under nitrogen until it was completely dry, again weighed
and then resuspended in the appropriate solvent to make
the solution of known concentration for the antibacterial
assay.