Potential Probiotic Yeasts Sourced from Natural Environmental and Spontaneous Processed Foods

In the last decades, there has been a growing interest from consumers in their food choices. Organic, natural, less processed, functional, and pre-probiotic products were preferred. Although, Saccharomyces cerevisiae var. boulardii is the most well-characterized probiotic yeast available on the market, improvement in probiotic function using other yeast species is an attractive future direction. In the present study, un-anthropized natural environments and spontaneous processed foods were exploited for wild yeast isolation with the goal of amplifying the knowledge of probiotic aptitudes of different yeast species. For this purpose, 179 yeast species were isolated, identified as belonging to twelve different genera, and characterized for the most important probiotic features. Findings showed interesting probiotic characteristics for some yeast strains belonging to Lachancea thermotolerans, Metschnikowia ziziphicola, Saccharomyces cerevisiae, and Torulaspora delbrueckii species, although these probiotic aptitudes were strictly strain-dependent. These yeast strains could be proposed for different probiotic applications, such as a valid alternative to, or in combination with, the probiotic yeast S. cerevisiae var. boulardii.