Pour Some Sugar on Yeast: the effects of rice sugar concentration on carbon dioxide production in yeast (Saccharomyces cerevisiae)

Abstract

Fermentation of sugars by yeast is an important process for the brewing and baking industries. We aimed to discover the effects of differing concentrations of rice sugar on yeast’s ability to perform anaerobic cellular respiration. We measured carbon dioxide production as our factor to compare the rates at which fermentation was being performed. We hypothesized that a greater amount of rice sugar would yield a greater amount of carbon dioxide, as sugar is essential in initiating glycolysis and then fermentation. Measuring carbon dioxide output by yeast at three sugar concentrations tested the hypothesis. Our hypothesis was not supported as our results indicated that the higher concentration of rice sugar yielded the lowest production of carbon dioxide, which may have been due to a severe change in the osmotic concentration gradient leading to osmotic stress in the yeast cells. Thus, producers of alcoholic beverages and bakers should be cautious to not exceed certain concentrations of sugar during the fermentation process.