Anti-aflatoxigenic capability and in vivo anti E. coli activity of the cyclic dipeptide-producing probiotic yeast

• Selected yeast isolate had proper adhesion and probiotic capabilities. • Anti-aflatoxigenic activity of the selected yeast isolate was verified. • In vivo safety and in vivo antibacterial activity of the isolate was approved. • The cyclic dipeptide-producing ability of the yeast isolate was verified. Potential applications of probiotics as efficient bio-preservatives have received considerable attentions. In the present study, Saccharomyces cerevisiae was PCR identified as the selected potential probiotic yeast isolated from whole wheat sourdough. The co-aggregation ability of the isolate with Escherichia coli (53.24%), as well as its inhibitory activity against E. coli (46.02%), was significantly ( P <0.05) higher than the other tested foodborne bacteria. The antifungal effect of the isolate on the studied fungi was also approved. The anti-aflatoxigenic capability of the yeast isolate led to 38.21, 46.40, 31.18 and 41.34% reduction of G 2 , G 1 , B 2 and B 1 aflatoxins, respectively according to the HPLC-based assay. Besides, in vivo anti- E. coli activity of the isolate was verified in the fed mice. According to the non-targeted metabolomics findings by the GC-MS analysis, a cyclic dipeptide and acetic acid were also identified as the most abundant antimicrobial compounds in the yeast cell-free supernatant. Accordingly, the yeast has a promising potential as probiotic protective culture or bio-control agent in different sectors.