Identification and Technological Characterization of Yeasts from Aksaray Çömlek Cheese

This study aimed to identify yeasts present in Aksaray Çömlek cheese and to assess their key technological characteristics. Eight traditionally produced Çömlek cheese samples were collected from local retail markets in Aksaray. Based on ITS sequencing, 28 yeast isolates were revealed as Yarrowia lipolytica (n=21), Pichia kudriavzevii (n=5), and Debaryomyces hansenii (n=2). For technological characterization, strain selection was based on representing each species in each cheese, resulting in 7 Y. lipolytica, 3 P. kudriavzevii, and 2 D. hansenii strains. Technological characteristics included proteolytic and lipolytic activities, alkalization capacity, and lactic acid assimilation under different salt concentrations. Among the tested isolates, Y. lipolytica CP8M1 displayed the strongest proteolysis, and several Y. lipolytica strains were highly lipolytic. In contrast, two P. kudriavzevii strains (CP1M3 and CP5M1) and two D. hansenii strains (CP5M3 and CP7M3) showed moderate proteolytic activity without lipolytic activity. All strains assimilated lactic acid. Among them, P. kudriavzevii CP5M1 and CP7M1 did not assimilate the lactic acid in the presence of NaCl. The halotolerant yeast D. hansenii was able to assimilate in 5% of NaCl, along with Y. lipolytica CP1M1 and CP6M1. Moderately lipolytic Y. lipolytica CP3M4 and proteolytic P. kudriavzevii CP1M3 and CP5M1, along with D. hansenii strains, appeared technologically favorable for contributing to aroma formation in Çömlek cheese. The findings contribute to a better understanding of the technological roles of indigenous yeasts in cheese production.