Detection of extracellular lipases and genotypic identification from yeast causing to spoilage of some dairy products produced in Gaziantep

Yeasts are usually detected in high numbers in dairy products reflecting a good adaptation to a substrate rich on proteins, lipids, sugars and organic acids. Wide distribution of yeasts is a consequence of proteolytic and lipolytic activity. In this study, our aim is to identify the yeast strains producing potential lipases and offer an alternative source to produce lipases by putting them into industrial microbiology. For this purpose, it was dilute of dairy products (yoghurt, cream, butter, curd cheese, Antep cheese) produced in Gaziantep, Turkey. Due to the isolation of yeasts steming spoilage from diluted samples, it was plated TGYCA (Tryptone Glucose Yeast Extract Chloramphenicol Agar) medium and incubated during 3-5 days at 30°C.After incubation, in order to obtain the pure culture of yeast isolates having apparent different morphologies(color, shape and size), by taking TGYCAmedium it was incubated during 3-5 days at 30°C. In order to detect the lipase enzyme, it was plated 66 isolates into PDA (Potato Dextrose Agar) medium containing tributyrin. Plated strains were incubated during 5-7 days at 30°C. At the end of the incubation, strains seemed clear zone around colonoies were regarded as pozitive strains in terms of lipase production. 20 strain accepted as positive were described at the molecular level.Among the 20 strain, the most frequently occurring yeasts belonged to the speciesKluyveromyces marxianus (40%), Candida intermedia(40%), Pichia fermentans (10%), Yarrowia lipolytica (5%), Kluyveromyces lactis (5%). Keywords: Spoilage yeasts, extracellular lipase, dairy products