Optimization of laboratory conditions for biosynthesis of type A trichothecenes

Abstract

Type A trichothecenes, T-2 toxin and diacetoxyscirpenol - DAS, belong to one of the most toxic groups of fusariotoxins. Although larger quantities of them can be found more often in cooler parts of Europe, regarding their metabolic characteristics and the types of illnesses they provoke, it is obvious that even smaller quantities of these toxins can cause serious health disturbances of humans and animals in climatic conditions of Serbia. Having in mind the importance of these substances, the aim of this study was to carry out the optimization of laboratory conditions under which screening of Fusarium spp. isolates from Serbia, regarding T-2 toxin and DAS production, should be done. Four cultures of Fusarium sporotrichioides originating from different regions throughout the world, were under present investigation: ITM-391 (Italy), KF-38/1 (Poland), M-1-1 (Japan) and R-2301 (Germany). According to the previous literature data, all of these isolates were T-2 toxin producers, and some of them were also DAS producers. The influence of medium composition (different C and N atoms sources microelements etc), as well as aeration (in liquid media), on biosynthesis process of these mycotoxins, in vitro conditions was investigated. In the case of most Fusarium sporotrichioides isolates, highest yields of T-2 toxin and DAS were achieved under the conditions of more intense aeration, and with the use of glucose (5 or 20%) as a C atom source. Fermentation in semi-synthetic liquid medium, using a rotary shaker, was more suitable for screening the toxicity of the fungal isolates in pure culture because of shorter period of incubation, more simpler sample preparation, obtaining less interfering materials in crude toxin extracts, and possibility for more precise definition of factors influencing the yield of trichothecenes.