Investigation of toxigenic potential of fungal species by the use of simple screening method

Abstract

Potential for the biosynthesis of aflatoxin B1 (AFLB1), ochratoxin A (OTA), diacetoxyscirpenol (DAS), T-2 toxin (T2), and zearalenone (ZON) was investigated in different fungal species belonging to the genera: Aspergillus, Fusarium and Penicillium. The majority of investigated isolates originated from cereal grains, crushed oil soybean seed and fodder mixtures. The simple screening method developed by Filtenborg et al. (1983) was applied with few modifications concerning the type of the medium and cultivation temperature. In order to optimise the biosynthetic conditions for different mycotoxins, the following control cultures, known as mycotin producers were used: OTA - A. ochraceus CBS 108.08, DAS - F. semitectum (SL-B i SL-C), T2 - F. sporotrichioides (ITM-391, M-1-1, R-2301) and ZON - F. graminearum (GZ-LES). The fungi were cultivated on the standard medium (YESA - 2% yeast extract, 15% sucrose and 2% agar, pH 6.5), three modifications of the basic medium (YESAZn - the standard medium supplemented with 0.23 mg/l ZnSO4 x 5 H2O; PPSA - the medium in which yeast extract was replaced with peptone-1; PPSAZn - the medium in which yeast extract was replaced with peptone-1 and supplemented with 0.23 mg/l ZnSO4 x 5 H2O), and the potato-dextrose agar (PDA). The earlier biosynthesis of tested mycotoxins was recorded under the following cultivation conditions of fungal species: AFLB1 - after 14 days on PDA at 27?1?C, OTA - after 10 days on YESA and YESAZn at 27?1?C, DAS - after 10 days on PPSA and PPSAZn at 27?1?C, T2 - after 7 days on PPSAZn and PPSA at room temperature (20-24?C), and ZON - after 1 week on YESA and YESAZn at room temperature (21-24?C).