Assessment of yeasts from winemaking environments: biosafety and functional perspectives on probiotic capabilities

Probiotic yeasts are gaining significant attention due to their numerousadvantages over traditional bacterial probiotics. Yeasts from winemakingenvironments may possess unique attributes that enhance their probioticpotential. In the present study, fourteen yeast strains were evaluated based onprevious in vitro studies regarding their biosecurity and tolerance togastrointestinal tract conditions. Biosafety was assessed using an in vivoinvertebrate model, specifically Galleria mellonella, and potential in vitroproperties, including enzyme production, antioxidant activity, antagonisticeffects against enteropathogens, and cholesterol- lowering capabilities, wereexplored. Notably, all strains were deemed biosafe. Assessment of enzymeproduction revealed that all strains produced lipase and phytase, while sixexhibited protease activity and five showed b-glucosidase activity. Allisolatesdemonstrated tolerance to oxidative stress, DPPH radical scavenging(with a maximum value of 76.46%), and hydroxyl radical trapping (with amaximum value of 85.69% in Wickerhamomyces anomalus). Antimicrobialactivity was also evaluated, with one strain producing siderophores.Furthermore, all strains exhibited catalase activity and produced short-chainorganic acids in varying proportions, including acetic acid (with a maximum valueof 1.436 g l-1 in W. anomalus), lactic acid (with a maximum value of 2.196 g lin Pichia manshurica), and propionic acid (with a maximum value of 2.312 g lin W. anomalus. All but one strain produced ethanol, with the highest value of 9.056 gl -1 observed in P. kudriavzevii. Importantly, all strains demonstrated the ability toreduce cholesterol levels in the medium to varying extents, with a reduction of upto 47.5% observed in P. kudriavzevii. These findings provide a robust foundationfor future investigations into the potential probiotic applications of these yeasts.