Deoxynivalenol and 15-monoacetyl deoxynivalenol production by Fusarium graminearum R6576 in liquid media

Growth and toxigenesis by Fusarium graminearum R6576, were compared in four liquid media. Parameters monitored during the fermentation were deoxynivalenol (DON) and 15-acetyl deoxynivalenol (15-ADON) production, fungal mass, carbohydrate utilization, and pH. Factors which were varied included basal medium composition, corn steep liquor (CSL) concentration, sucrose concentration and ammonium tartrate concentration. Growth in modified Fries medium resulted in only low levels of DON (0.25 mg/ L) and 15-ADON (0.25 mg/ L) after 20 days. Addition of 4% CSL to modified Fries medium raised the 20 day DON yield to 16.5 mg/ l. Increasing the sucrose concentration in modified Fries medium amended with 4% CSL resulted in increased mycelial dry weight but decreased levels of DON. Concentrations of ammonium tartrate greater than 1% in modified Fries amended with 4% CSL greatly reduced DON yield. Use of glucose-yeast extract-peptone (GYEP) for toxin production resulted in higher yields of 15-ADON (14.0 mg/ L) than DON (5.5 mg/ L) after 20 days. However, supplementation of GYEP with 4% CSL resulted primarily in DON production (4.5 mg/ L) after 20 days. In general, qualitative and quantitative production of DON and 15-ADON by Fusarium graminearum R6576 were dependent on the composition of the complex liquid medium.