ISOLATION AND CHARACTERIZATION OF THE DOMINANT YEAST FROM INGREDIENTSOF TELLA, THE TRADITIONAL FERMENTED ALCOHOLIC BEVERAGE

Abstract

Tella” is one of the important Ethiopian traditional beverages, which is prepared from different ingredients. Ingredients of tella are one of the major important sources of the isolation of dominant yeast from the local alcoholic beverages. Hence, this study was conducted to determine the major source of dominant yeast cells by identifying them in the ingredients of tellasuch as; gesho, bikil, tense, difdif and compared within that of bakery yeast. The collected samples were processed to isolate yeasts using Yeast extract potato dextrose agar amended with 0.1 g/L chloramphenicol. Four yeasts were isolated from theIngredients of tella tella were compared within that of the bakery yeast in terms of morphological and physiological characteristics such as shape, vegetative reproduction, ascospore formation, colony count, and Carbon dioxide production by using six sugar in the Durham tubes. The current result showed all of the yeast isolates were creamy to white color and ovoid to spherical microscopic shape. Bikil, Difdif, Gesho, and Tinsis yeast isolates with their sugar fermentative abilities were selected and tested for Carbon dioxide production. The optimum growth pH and temperature values for all selected yeast isolates were recorded as 5 and 30℃, respectively, in Yeast extract potato dextrose agar medium. Among them, Bikil, Gesho, and Tinsis isolate were found to produce more desirable carbon dioxide in the Durham tube than Difdif. All yeast isolates were identified as Saccharomyces spp. Based on Cell Count of Selected Yeast Isolates, Bikil contained 6.9 x 106 cfu/ml yet Gesho contained 5.2 x 106 cfu/ml, Tinsis contained 4.5 x 106 cfu/ml, and Difdif contained 3.6 x 106 cfu/ml but that of the bakery yeast contained 1.12 x 107 cfu/ml. Thus, bikil was considered the major source of the dominant yeast from ingredients of tella. As well as in this study, the source and type of the dominant yeast in the beverages at the consumption stage was identified.Over-all the results of this study showed the yeast isolates from “tella” showed good fermentative capability as compared to the commercial S. cerevisiae strains, which are used as controls for this study and Moreover, the finding of the present study provide a promising source of noble beer yeast isolates with quality aroma and color