Determination of Enzyme Profiles and Molecular Characterization of Yeast Species Isolated from Butter Samples

Abstract

Constituting the most important group of microorganisms that offered to human consumption through food, yeasts are a substantial part of microflora in dairy products. Due to sophisticated enzyme production especially high proteolytic and lipolytic activities, some of the yeast species play an essential role in many processes such as fermentation, ripening, production of aroma precursors and deterioration in dairy product indicating these products as a source of extracellular enzyme producer yeast strains.  In this study, butter samples were collected from delicatessens and grocery stores in different locations in Izmir province in order to isolate enzyme producers. A total of 40 yeast strains were isolated and investigated for their lipase, protease and amylase activities on solid medium consisting of tributyrin, skim milk and starch, respectively. Sixteen yeast isolates were found to be positive for enzyme production. Lipase and protease activities were observed in 11 yeast strains (68,75%), while only one yeast strain (6,25%) was found to be positive for protease and amylase production. 4 of yeast strains (25%) were able to produce only lipase enzyme. Molecular characterization of the yeast strains based on 26S rRNA region D1/D2 domains revealed that the isolates belonged to Candida zeylanoides (62,5%) and Pichia fermentas (37,5%) species.