Pichia fermentans KCB21_L2 D1-D2
The presence of mycotoxins in food poses a significant risk to food safety, and it is essential to develop effective and safe detoxification strategies. In this study, we demonstrate the strong ability of Pichia fermentans KCB21_L2, a yeast isolated from kefir, to detoxify aflatoxin B1, fumonisin B1 and ocratoxin A. Viable cells removed aflatoxin B1 and fumonisin B1 more efficiently than heat-inactivated cells, particularly at pH values of 5.5 and 7.0, suggesting the involvement of an active detoxification process. Subsequently, we evaluated the capacity of P. fermentans KCB21_L2 to eliminate higher mycotoxin concentrations and investigated the underlying molecular and cellular responses. The yeast effectively removed high levels of all three mycotoxins. Transcriptional analysis revealed the activation of metabolic pathways related to amino acid catabolism and fatty acid metabolism, likely reflecting an adaptive stress response. However, no significant upregulation of specific genes related to mycotoxin-degrading enzymes was observed. In conclusion, the detoxification process may involve multiple factors, including stress response pathways, possible production of organic acids, adsorption of mycotoxins into the cell wall, and constitutively expressed enzymes capable of degrading mycotoxins. In general, these findings highlight the multifactorial nature of yeast-mediated mycotoxin detoxification and establish P. fermentans KCB21_L2 as a promising candidate for safe biological detoxification in food systems.