The study was performed in a batch system in order to determine the effects of pH and temperature on growth and glycerol production kinetics of two indigenous wine yeast strains Saccharomyces cerevisiae Kalecik 1 and Narince 3. The highest values of dry mass and specific growth rate were obtained at pH 4.00 for both of the strains. Maximum specific glycerol production rates were obtained at pH 5.92 and 6.27 for the strains Kalecik 1 and Narince 3, respectively. Kalecik 1 strain produced maximum 8.8 gL -1 of glycerol at pH 6.46. Maximum glycerol concentration obtained by the strain Narince 3 was 9.1 gL -1 at pH 6.48. Both yeasts reached maximum specific growth rate at 30ºC. Optimum temperature range for glycerol production was determined as 25-30ºC for the strain Kalecik 1. The strain Narince 3 reached maximum specific glycerol production rate at 30ºC. Maximum glycerol concentrations at 30ºC were obtained as 8.5 and 7.6 gL -1 for Kalecik 1 and Narince 3, respectively.

Yeasts, associated with secondary flora of many cheese types, are important microorganisms for cheese ripening process. The aim of this study was to identify the yeasts isolated from traditional Mihalic cheese and to determine their enzymatic activities as a tool for their technological characteristics. Phenotypic identification was performed by using API ID 32C test system and some complementary morphological, physiological and biochemical tests. Enzyme profiles of the isolates were determined by using API-ZYM strips. In this study, 72 yeast isolates were obtained from 29 Mihalic cheese samples. Fifty-six (78%) of the isolates could be identified at species level, and one isolate at genus level. The identified yeast species belonged to three genera; Candida, Geotrichum and Trichosporon. It was determined that Candida famata var. famata was the dominant species in Mihalic cheese. The yeast isolates had variable enzyme activities including acid phosphatase, esterase, esterase lipase, lipase, β-galactosidase, leucine arylamidase, valine arylamidase and cysteine arylamidase, which could have important attributes during cheese ripening. C. famata var. famata M22, Candida guilliermondii var. membranefaciens M54 and Candida tropicalis M2 were selected to be superior strains on the basis of their enzyme profiles. Identification and enzymatic characterization of the yeasts originated from Mihalic cheese was performed for the first time in this study.

The composition of the essential oil from aerial parts of Thymbra spicata L. from Turkey was analysed by GC-MS and its in vitro antimicrobial activity was examined. GC-MS analysis of the essential oil resulted in the identification of twenty-three constituents, representing 97.04% of the oil. The major compounds detected in the essential oil were carvacrol (60.39%), gamma-terpinene (12.95%), and p-cymene (9.61%). The in vitro efficacy of the essential oil against 21 bacteria and seven Candida species was examined using disc diffusion and minimum inhibitory concentration (MIC) methods. The essential oil demonstrated strong anti-microbial activity in a wide spectrum against most microorganisms, particularly the yeasts tested. This is the first report on the anticandidal properties of the essential oil of T. spicata. In conclusion, this study confirms that T. spicata essential oil could be considered as a natural antimicrobial source.

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