Screening of soil cyanobacteria for antifungal and antibacterial activity

Abstract

Soil cyanobacteria isolated from the paddy fields of seven provinces in Iran was evaluated for antimicrobial activity. Aqueous, petroleum ether, and methanol extracts from 76 microalgae were examined for antimicrobial properties against four bacteria and two fungi. Of total microalgae, 22.4% (17 cyanobacteria) exhibited antimicrobial effects. Selected cyanobacteria with positive antimicrobial activities were members of the families Stigonemataceae, Nostocaceae, Oscillatoriaceae, and Chroococcaceae. Growth of Bacillus subtilis Persian Type Culture Collection (PTCC) 1204 and Staphylococcus epidermidis PTCC 1114 were inhibited by 12 and 14 species of cyanobacteria, respectively. Also, eight cyanobacteria inhibited the growth of Escherichia coli PTCC 1047, and two species inhibited the growth of Salmonella typhi PTCC 1108. Considering fungi, six species inhibited the growth of Candida kefyr ATCC 1140, and one cyanobacterium species inhibited the growth of Candida albicans ATCC 14053. Furthermore, one of the paddy fields (Khozestan) showed no antimicrobial activity. © 2005 Taylor & Francis Ltd.