Antifungal and Antibacterial Activity of the Microalgae Collected from Paddy Fields of Iran: Characterization of Antimicrobial Activity of Chroococcus dispersus

Abstract

Antifungal and antibacterial activity of the microalgae from paddy fields in the south of Iran were studied. Soil samples were collected from paddy fields of Fars province and were cultured in BG11 medium. Supernatants, methanolic and hexane extracts from biomass of 60 strains of microalgae were isolated and screened against six strains of bacteria and four strains of fungi. The culture supernatants of 21 strains of microalgae and methanolic extracts of 8 strains exhibited significant antibacterial effect and 17 strains showed antifungal effect. No antimicrobial activity was detected in the hexane extracts and no methanolic extracts inhibited the growth of fungi. In present screening, Chroococcus dispersus, Chlamydomonas reinhardtii and Chlorella vulgaris appeared to be the most promising strains and it was shown that they excreted a broad spectrum of antimicrobial substances in the culture medium. Among all of the species studied in this investigation for antibacterial and antifungal activity, Chroococcus dispersus PTCC 1677 indicated widespread spectrum of antimicrobial activities. Bioautography and Bioassay-guided fraction of culture medium of the Chroococcus dispersus exhibited a polar substance in the culture medium as well.