Determination of some extracellular enzymatic activities and molecular identification of Kluyveromyces marxianus yeast species isolated from diary products

Natural habitats of yeast are quite varied. Due to its content, dairy products is very suitable environment for the yeasts. Many studies conducted on the identification of yeast species isolated from dairy products. In our research, we described yeast in raw milk, yoghurt, ayran and cheese samples collected from Çanakkale, Turkey. In addition molecular characterization of isolated Kluyveromyces marxianus yeast species were done. Extracellular enzyme activities of yeast species were determined and their glucose repression patterns uncovered.In our study, twenty two different yeast species were identified from dairy products as Candida inconspicua, Candida norvegensis, Candida lambica, Candida tropicalis, Candida zeylanoides, Candida lipolytica, Candida utilis, Candida parapsilosis, Candida famata, Candida colliculosa, Candida pelliculosa, Candida lusitaniae, Candida sake, Candida melibiosica, Candida intermedia, Candida guillermondii, Rhodotorula muciloginosa, Rhodotorula glutinis, Geotrichum capitatum, Saccharomyces cerevisiae, Kluyveromyces lactis and Kluyveromyces marxianus. After molecular analysis of 66 K. marxianus yeast strains, 2 haplotype patterns were found. Extra cellular enzyme profiles of K. marxianus yeast strains were different between the strains. Invertase, inulinase and ? -galactosidase enzyme activities determined in both repres and derepres conditions were very changeable between strains.The metabolic, and so genetic, responses of K. marxianus yeast strains against environmental factors were different. Physiological responses of yeast cells to environmental conditions were also different. Glucose, itself, was not enough for repressing the genes related with the utilization of other carbon sources. Glucose sensors and transporters that are not identified yet in K. marxianus species may responsible from these variable results.