Let’s Get This Bread: Investigating how the relation of sugar complexity contributes to Saccharomyces cerevisiae’s CO2 emission.

Alyssa Pauzuolis, Kennedy McAllister, Abigail Grathwohl, Jordyn Leach


Yeast is a common and crucial element for bakers and brewers to successfully make their product, given its ethanol production through its fermentation process, in which carbohydrates are metabolized to emit CO2. To contribute to the discussion of Acme Baking and Brewing, we conducted an experiment using Baker’s yeast (Saccharomyces cerevisiae) and measured its CO2 emission when exposed to various complex sugars: dextrose, sucrose, and cellulose. We hypothesized that sucrose would trigger a higher CO2 emission with the Baker’s yeast because of its properties as a disaccharide. Sucrose, through the process of glycolysis and fermentation, breaks down into fructose and glucose to provide more beneficial elements to the cellular respiration of Baker’s yeast (Crow et al. 2016). After the disaccharide is broken down into the two sugars, fructose is converted to another glucose molecule through isomerase (Hewitson et al. 2019), providing double the amount of glucose for S. cerevisiae to ferment. With cellulose, a polysaccharide, being more complex than sucrose, a disaccharide, it would be more difficult to break down. Meanwhile, dextrose could not provide the adequate amount of energy on its own for S. cerevisiae’s metabolism to excel. We found that our hypothesis was supported and that the qualities of sucrose provided the necessary elements for yeast to metabolize at a better rate.


cellular respiration, CO2 emission, yeast, complex sugars

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