ZEARALENONE PRODUCTION IN SABOURAUD DEXTROSE BROTH AND RICE CULTURE BY VARIOUS SPECIES OF FUSARIUM FUNGI

ABSTRACT Zearalenone (ZEN) is an estrogenic mycotoxin produced by Fusarium fungi. Pure preparations of the toxin should be available for in vitro and in vivo studies. The growth medium affects the activity of the fungus and the production of the toxin. ZEN producing capacity of three Fusarium species (F. oxysporum, F. graminearum, and F. solani) and the effects of Sabouraud Dextrose Broth (SDB) and rice culture on the ZEN production were investigated. The Fusarium fungi were incubated in SDB and rice culture at a constant temperature of 25°C for 30- and 48-day periods respectively. HPLC with fluorescence detection was used to measure the concentrations of ZEN. The amounts of ZEN produced by various Fusarium species on SDB were not statistically different. However, the quantity of ZEN produced on rice culture was significantly higher for F. graminearum compared to the amounts produced by F. oxysporum and F. solani (P<0.001). F. graminearum produced significantly higher amounts of the toxin (P<0.001) on rice culture than on SDB. In fact, the highest amount of ZEN production was seen by F. graminearum on rice culture. The amount of ZEN produced by F. oxysporum and F. solani were not different between SDB and rice cultures. The in vitro ZEN production by Fusarium fungi may be different on SDB and rice culture. F. graminearum can produce higher amounts of ZEN on rice medium compared to SDB. The activities of F. oxysporum and F. solani appear to be almost similar on these media. Keywords: Fusarium species, Rice, media culture, SDB, Zearalenone