A novel rapid screening method for identifying aflatoxin B₁-degrading Agaricales

Abstract Aflatoxin B₁ (AFB₁) is one of the most toxic and widespread mycotoxins, representing a serious threat to food safety and public health. In this study, a rapid screening method was developed to identify fungal strains capable of degrading AFB₁, using mushrooms belonging to the order Agaricales. Fifteen strains were evaluated, including isolates obtained from different regions of Argentina as well as commercially used strains. The fungi were inoculated onto Coconut Milk Agar (CMA), with and without the addition of AFB₁. Fungal growth on both media was assessed, and toxin degradation was evaluated by the reduction of fluorescence under UV light (365 nm), subsequently confirmed by high-performance liquid chromatography with diode array detection (HPLC-DAD). All strains exhibited a reduction in growth rate in the presence of AFB₁. Among the 15 strains analyzed by HPLC-DAD, ten achieved complete degradation of AFB₁ to undetectable levels (>99% degradation), while three showed partial degradation (84%, 62%, and 20%). Notably, two strains (Cyclocybe cylindracea and Stropharia sp.) degraded AFB₁ despite the absence of visible mycelial growth, suggesting the involvement of extracellular enzymatic activity. These results demonstrate that several Agaricales species exhibit a high potential for AFB₁ degradation. The proposed method represents a rapid, low-cost, and effective tool for the preliminary identification of aflatoxin-degrading strains, showing a high concordance with quantitative HPLC-DAD results, and highlighting its promising applicability in bioremediation programs.