Differentiation of Saccharomyces boulardii from Saccharomyces cerevisiae Strains Using the qPCR-HRM Technique Targeting AAD15 Gene.

S. boulardii, the probiotic variety of S. cerevisiae, is known for its different characteristics, even though the two strains share more than 99% genomic relatedness. Therefore, S. boulardii has been examined and evaluated for differential characteristics in many studies. This study aims to explain the differentiation of S. boulardii from well-identified S. cerevisiae strains by biochemical characteristics and the qPCR-HRM. Initially, S. cerevisiae isolates from the HUF Culture Collection, were screened for basic biochemical characteristics such as growth temperature, glucose, and galactose utilization tests. Out of all selected cultures, the viability at gastric pH was investigated by spectrophotometric readings. The results showed that one isolate was more resistant than other strains when exposed to gastric acids. After sequencing and phylogeny steps using LR0R universal primer, there was no significant differentiation for S. boulardii strains and therefore HRM analysis was performed to interrogate sequence variation and differentiate S. boulardii strains. HRM analysis has successfully distinguished even highly closely related yeast strains. [ABSTRACT FROM AUTHOR]