Structural analysis of enniatin H, I, and MK1688 and beauvericin by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and their production by Fusarium oxysporum KFCC 11363P

Abstract

The molecular structures of enniatins H, I, and MK1688 and beauvericin were investigated by liquid chromatography-tandem mass spectrometry (LC-MS/MS). MS fragmentation occurred by loss of -CO after opening of the cyclic molecule to carbonyl carbon, and cleavage of the peptide and ester bonds in the molecular structure. Fusarium oxysporum KFCC 11363P was tested for its ability to produce beauvericin and enniatins H, I, and MK1688 on five cereal substrates: rice, barley, maize, wheat, and Indian millet kernels. Furthermore, optimal conditions for the production of the four mycotoxins by the Fusarium isolate were examined on maize at four temperatures (15, 20, 25, and 30°C) and at three moisture contents (10, 20, and 40%). Large amounts of beauvericin and enniatin H were present in maize cultures at 25°C (232.4 and 196.4 µg g−1, respectively). Enniatins I and MK1688 were maximally formed at 20°C (221.5 and 180.2 µg g−1, respectively). The optimal moisture contents for the production of enniatins H (196.4 µg g−1) and MK1688 (165.6 µg g−1), were 40%.