Saccharomyces cerevisiae MYSY1 as a promising probiotic isolate with antifungal properties against foodborne Aspergillus species

Studies on yeast as a beneficial microorganism are still in the early stages, with Saccharomyces boulardii being the most researched. In the present study, a total of 15 different yeast strain were isolated from Neera collected within Karnataka. Following a screening process, one promising strain, Saccharomyces cerevisiae MYSY1 was chosen for the further examination. Preliminary characterization and biochemical analysis revealed that Saccharomyces cerevesiae MYSY1 displayed promising probiotic characteristics, including the ability to survive acidic conditions, with a survival rate of over 65 %, and a strong adhesion rate of 74.5 % over 5 h. Moreover, Saccharomyces cerevesiae MYSY1 demonstrated strong antifungal capabilities by causing disorientation and structural changes in the mycelium and conidia of Aspergillus niger and Aspergillus fumigatus. The study also found that both Volatile Organic compounds (VOCs) and cell-free supernatant (CFS) from Saccharomyces cerevisiae MYSY1 hindered the growth of mycelium. Conidia germination was inhibited by over 19.14 % with VOCs and over 36.05 % with CFS. Cell membrane integrity was assessed by staining with propidium iodide, and ergosterol content was measured, revealing a reduction of over 24 % in ergosterol content in treated mycelium. Scanning Electron Microscopy (SEM) analysis showed that Saccharomyces cerevisiae MYSY1 significantly inhibited the fungal growth by damaging the hyphae. Therefore, Saccharomyces cerevisiae MYSY1, isolated from Neera, exhibited potential probiotic attributes with antifungal activity, establishing it as a probable candidate for use in the food industry.