MORPHOLOGICAL-CHANGES ASSOCIATED WITH THE CELLULAR AGING OF A BREWINGYEAST-STRAIN

The yeast Saccharomyces cerevisiae possesses a finite replicative life span-each individual cell is capable of only a limited number of divis ions before the onset of senescence and, finally, death. Methods to in vestigate the aging process in laboratory yeast strains have been deve loped but have never been applied to the less genetically tractable br ewing yeasts. Therefore, the effects of cellular aging on fermentation performance are not known. Characterization of the aging profile of a lager yeast strain and age-related changes in cellular morphology are reported here. It is suggested that aging and senescence of yeast cel ls may play a role in ''hung fermentations'' and related problems some times experienced by the brewing industry.