production and characterization of antimicrobial active substance from spirulina platensis.

background and objectives: the present work was carried out to investigate the ability of spirulina platensis to produce antimicrobial substance against bacteria and fungi.  materials and methods: the cells of the cyanobacterium were subjected to different extractions and the purified antagonistic compound proved to be effective against broad spectrum of bacteria and fungi. the antagonistic compound was purified using thin layer chromatography. results: the results indicated that the ir spectrum showed bands at 1269 cm(-1), 1414 cm(-1) (c-o-c), 1643 cm(-1) (co of amide),1563 cm(-1) (c = c) and broad band 3441 cm(-1) (of oh and nh)., (1)hnmr showed δ 0.8 (-ch3), δ 1.2 (-ch2), δ 4.2(-oh), δ 7.2(-nh), δ 7.4 and δ 7.7 (aromatic ch)., mass spectrum showed molecular ion beak at m/z = 341 (abundance (0.03%). also, the elemental analysis gave molecular formula,c15h18no8. conclusion: the purified antimicrobial compound produced by s. platensis was more active against gram positive, gram negative bacteria and unicellular fungi, c. albicans. the highest biological activity was recorded against escherichia coli, pseudomonas aeruginosa, bacillus subtilis and aspergillus niger. the results of this investigation proved that cyanobacteria could be a good source for production of antimicrobial agents which could be effective when compared with contemporary antimicrobial compounds.