Antimicrobial activity of Cyanobacteria isolated from hot spring of Geno

3 Abstract: Cyanobacteria (blue-green algae) are rich sources of structurally novel and biologically active metabolites. Recent studies indicate the presence of some bioactive compounds in the blue green algae which are shown to exhibit anticancer, antimicrobial, antifungal or anti-inflammatory and other pharmacological activities. The present study aimed to collect and identify cyanobacteria from hot spring of Geno in Bandar Abbas province. Totally 21 species of cyanobacteria were collected and cultured in BG-11 medium. Based on their growth characteristics; seven species namely Oscillatoria subbrevis, O. tenuis, O. limentica, O. angusta, O. articulate, Synechocystis aquatilis and Synechoccous cerdorum were selected for the production of antimicrobial agents against five Gram-positive (Bacillus subtilis, B. pumulis, Enterococcus fecalis, Staphylococcus aureus and S.epidermidis) and three Gram-negative (Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae) bacteria and two fungi (Candida albicans and Saccharomyces cerevisiae). The results of this study showed that the methanol extracts exhibited high antimicrobial activity against some Gram positive bacteria (Bacillus subtilis and B. pumulis), moderate antibacterial activity against the some Gram negative organisms (Escherichia coli) and moderate antifungal activity against some fungi (S. cerevisiae).