MOLECULAR IDENTIFICATION AND CHARACTERIZATION OF YEAST SPECIES ISOLATED FROM FERMENTATION FOOD

The Molecular identification and characterization of yeasts isolated from fermentation food stuffs in Sari, north Iran, were investigated. The yeasts involved in the fermentation food stuffs were found to consist of Saccharomyces spp. almost exclusively. Of yeast species isolated investigated, 27.4% were identified as Saccharomyces cerevisiae, whereas more than half of the isolates [72.6%] had physiological properties of other yeast for example K. lactis، K. marxianus P. manshurica، P. membranifaciens، P. occidentails، P. kudriavzerii، Z. paradaii، C. pseudoasrei، C. paraugosa، T. delbrueckii been reported. Identification of Species Saccharomyces utilizes diagnostic tests of yeasts such as the growth of yeast colonies in culture media enriched [YPD, SDA] and CHROM agar and tests differential diagnosis of Urease test, germ tube test and corn meal agar with Tween 80 were culture. Both ITS PCR- RFLP and Sequencing strongly indicated that these isolates were related to S. cerevisiae, regardless of their phenotypic characteristics. Besides, identity the genus and species on the basis of Coverage Query and Max is done, that highest percentage of samples similar to sequences in the gene bank title is.The results showed that all isolates had individual profiles, although some profiles the spontaneous fermentation by a variety of strains of S.cerevisiae were closely related. Such variations from fermentation food stuffs might be attributed to local deviations in the production, among which starter cultures should be selected. Keywords: Fermentation, S.cerevisiae, YPD, SDA, CHROM agar, PCR RFLP, Sequencing