Characterization of yeast isolated from sourdough microbiota with different DNA marker systems and determination of some technological properties

Within the scope of this thesis, it was aimed to isolate yeasts from Type I sourdough samples collected from different regions and provinces of Turkey, conduct molecular characterization, and determine strains with industrial importance. For this purpose, 345 endogenous yeast strains were isolated from 65 Type I sourdough samples collected from different regions and provinces of Turkey, and molecular characterization was performed using 9 iPBS and 7 SCoT markers. The sequencing of ITS regions of yeasts selected from different species and intraspecific polymorphic strain revealed that the microbioato included S. cerevisiae (n=290), K. servazzii (n=23), K. humilis (n=11), W. anomalus (n=10), T. delbrueckii (n=9), and P. kudriavzevii (n =2) species. Both iPBS and SCoT markers have yielded very successful results in distinguishing species from each other, supported by high PIC and RP values. As a result of the population analysis of S. cerevisiae strains using both marker systems, three main genotypes (ΔK=3) were obtained according to the STRUCTURE analysis. According to AMOVA results, significant differences were obtained between regions (P<0.001). Obtaining high correlation (r=0.98) between different data matrixes led to combining the data matrixes to get a new UPGMA dendrogram. As a result, a total of 50 endogenous yeasts and 5 commercial yeast strains were chosen to be examined in terms of various technological properties (Growth at different pH values, NaCl concentrations and temperatures, resistance to lactic acid, acetic acid and potassium sorbate, phytase activity, leavening activity and fermentation capacity). There was no significant difference between different genotypes and technological characteristics (P<0.05). The statistical TBA method was used to determine the technologically prominent yeast strains and 11 endogenous S. cerevisiae strains were found to be technologically superior. To sum up, the findings of this study will provide useful information for researchers studying the genetic differentiation of yeasts according to populations and their technological characteristics.