Formation of ( super(13)C)- and ( super(14)C)zearalenone by Fusarium graminearum DSM 4529

To raise the yields for the production of super(14)C-labelled zearalenone in Fusarium cultures the influence of growth conditions and known effectors or precursors of toxin biosynthesis was studied. Benzoic acid and 2,4-dihydroxybenzoic acid used as precursors decreased toxin formation; in the presence of different pesticides such as 2,4-D, however, toxin production increased up to 140%. The known pathway of zearalenone biosynthesis could be confirmed from the relative extents of super(13)C-incorporation into the zearalenone molecule by incubating Fusarium graminearum DSM 4529 with D-(+)-(1- super(13)C)glucose as carbon source. When grown in the presence of D-(U- super(14)C)glucose or (2- super(14)C)malonic acid the strain produced ( super(14)C)zearalenone with specific activities of 0.07 and 0.09 mu Ci/mg, the super(14)C-incorporation rates being 0.34% and 0.48%, respectively.