In this study Oscillatoria princeps were isolated ،purified and identification
from water canal in Almustansiriah University . BG-11 culture media was used for
their cultivation in suitable laboratory conditions (25c°, 200μE/mP
2
P/sec) for 16:8 hrs.
Light: dark. Each culture was harvested at the end of exponential phase .Organic
solvents used for extraction was Chloroform: methanol at 2:1 to extract the crude
active Intracellular and Extracellular substances, and evaporated down to dryness.
Antibacterial activity of these different extracts were evaluated against 10 strains of
gram positive bacteria and gram negative bacteria, Agar diffusion method was used
in this evaluation. Results showed that the intracellular products which extracted
beast than extracellular product. The gram positive bacteria studied revealed higher
susceptibility to attack by the intracellular and extracellular extracts comparing with
the gram negative bacteria. The intercellular extraction revealed higher antibacterial
activity against Staphylococcus arueus average of inhibition zone was 30mm. but
The extracellular extraction revealed higher antibacterial activity against Bacillus
subtilise average of inhibition zone was 28 mm. However, Results showed gram
negative bacteria intracellular products extract has the antagonistic activity against
Pseudomonas aeruginosas with 25 mm inhibition zone. also been detected on some
fatty acids produced by the algae O.princeps which Palmitic , Stearic, Arachidic ,
Linoleic and Linolenic . the highest rate is fatty acid Palmitic 75% of the extract
intercellular while the rate of 34% of the acid fatty Linolenic to extracellular
abroad.