Effects of ¹⁴C-labelled precursor feeding on production of beauvericin, enniatins H, I, and MK1688 by Fusarium oxysporum KFCC11363P.

The effects of ¹⁴C-labelled precursor feeding on the production of cyclic hexadepsipeptides were investigated by the mycelium of F. oxysporum KFCC11363P producing beauvericin along with enniatins H, I, and MK1688. Most ¹⁴C-phenylalanine and ¹⁴C-valine were incorporated easily into the biosynthetic pathway of ¹⁴C-labelled beauvericin in vivo by the mycelium. However, only a small amount of ¹⁴C-labelled enniatins could be detected by feeding of ¹⁴C-valine. When L-valine was fed as a precursor to the mycelium at large scale, the level of beauvericin increased to maximum followed by enniatins H and I. Feeding of L-valine did not affect the production of enniatin MK1688. These results suggest that L-valine feeding led to the production of D-hydroxyisovaleic acid in the mycelium and specifically enhanced the production of cyclic hexadepsipeptides containing D-hydroxyisovaleic acid, such as beauvericin and enniatins H and I.