Isolation and Characterization of Temperature and Ethanol Tolerant Strain of Saccharomyces cerevisiae Strains From Naturally Fermented Juices

Abstract

Saccharomyces cerevisiae is common yeast of economic importance in food and brewing industries. This study aimed at isolating the yeast from local sources, viz. Toddy, Date palm toddy, Fermented dough, Fermented fruit juice of apple and orange and then characterized on the basis of their morphology, microbial count, temperature, ethanol tolerance, flocculation, and fermentative ability and on stress test, to see if they can serve as a sources for industrial purposes. Some of them were found to possess high temperature and ethanol tolerance ability, some had high flocculation and fermentative capacity and survived when subjected to various stress conditions. Saccharomyces cerevisiae isolated from these local sources can be used effectively in the bakery and brewing industries. The yeast isolated from date palm has ability to grow at low temperature, have high ethanol tolerance ability and high flocculation ability. Likewise yeast isolated from toddy has ability to grow at high temperature and also have good ethanol tolerance ability. The ability of yeast to flocculate have benefit of easy separation from the final product at the end of fermentation without filtration/centrifugation and it is a important source for bakers industry while yeast that have good ethanol tolerance ability and high temperature tolerance ability can be use in alcoholic industry from various sources.