Optimization of BG11 culture medium for increasing antifungal activity of Cyanobacterium sp. PGU1 against some plant pathogenic fungi

Cyanobacteria have been considered due to producuction of types of secondary metabolites and antimicrobial compounds. This research designated for optimization of BG11 culture medium to increase the antifungal activity of Cyanobacterium sp. PGU1 against the plant pathogenic fungi, Fusarium oxysporum f. sp lycopersici and Rhizoctonia solaniAG2-2-IIIB. Cyanobacterium was isolated from the Persian Gulf and identified as Cyanobacterium sp. using morphological characteristics and 16S rRNA sequencing. Optimization was done by changing the amount of nitrogen (NaNO3) (0.75, 1.5 and 3 g/l) and phosphate (K2HPO4) (0.02, 0.04 and 0.08 g/l) and then the antifungal activity of cyanobacterium was investigated. Antifungal effects of pure culture methanol extract of cyanobacterium were investigated under in vitro conditions by mixing the extract derived from pure culture before and after optimization to the pathogen culture medium. Growth inhibition percentage for F. oxysporum f. sp. lycopersici and R. solani AG2-2-IIIB increased from 79.33 to 87.43, and from 82.47 to 90.62 percent, respectively.