Isolation, Characterization and Identification of Yeast (Saccharomyces Cerevisiae) From Three Local Beverage Drinks

Abstract

Saccharomyces cerevisiae is a common yeast of economic importance in food and brewing industries. They are obtained commercially from foreign suppliers and are costly. Their high cost renders the cost of their products too high for consumers. This study aimed at isolating the yeast from local sources, characterize them and check their morphology, count, temperature and ethanol tolerance, flocculation and fermentative ability as well as stress exclusion test, to see if they can serve as alternative sources for industrial yeast. The isolated yeast and their beverages were designated as FY, isolated from fura(millet meal),BY, isolated from burukutu (local sorghum drink) and GY from grape juice. The isolated yeasts showed colony count ranging from 3.0-2.7x 10 5 cfu/ml while the commercial baker’s yeast showed a colony count of 3.5x10 5 cfu/ml. They all had high temperature and ethanol tolerance above 45 0 C and 15% respectively as well as high flocculation ability, exhibited high fermentative capacity and survived when subjected to various stress conditions. The characteristics exhibited by the isolated yeast compared favourably with that of the commercial yeast(CY). Saccharomyces cerevisiae isolated from these local sources can be used effectively in the bakery and brewing industries.