Abstract

Bioassay is an alternative screening technique to evaluate the biotoxicity of the fungal secondary metabolites before any further chemical analyses. In this study, the cell density of Chlorella vulgaris cultures were used to detect the biotoxicity of 108 isolates belonging to seven fungal species. The crude extracts of all toxin producing fungal isolates that were tested inhibited the growth of C. vulgaris dramatically after 48 and 72 h as compared to the control. The crude extracts of the nontoxin producing fungal isolates that were tested showed that there was no significant inhibition of C. vulgaris at the three time intervals as compared to the control. These results corresponded to the Bacillus subtilis disk diffusion method. The use of optical density readings of the growth of C. vulgaris reflected a rapid, easy and effective tool to detect mycotoxins. 

Key words: Bioassay, Chlorella, colorimetric, mycotoxins, pathogenicity.