Let it rise: the relationship between sugar complexities and temperature on ethanol production of Saccharomyces cerevisiae

Abstract

Saccharomyces cerevisiae, or baker’s yeast, is used to make bread and other baked goods, along with other products, such as beer. It is identified as a fungus and needs energy to grow. When different types of sugars are combined with this yeast, a process known as fermentation occurs. This is where the yeast can obtain energy from the sugar, which in turn produces carbon dioxide and ethanol, causing the dough to rise. Because of this, it was believed that simple sugars at warmer temperatures would allow the yeast to produce the most ethanol. This led to the hypothesis that the glucose would produce the most ethanol, followed by sucrose, and lastly, starch and all three would produce more ethanol in 35℃ than 23℃. In this study, three different types of sugars known as glucose, sucrose, and starch were combined with yeast to evaluate which sugar produced the most ethanol and carbon dioxide. This was repeated three times for each sugar across two temperatures of 23°C and 35°C, each trial lasting ten minutes. These results will be determined by using a temperature probe, ethanol probe, and Logger Pro software.   The results partially supported the hypothesis. While the sugars when mixed with baker's yeast did have a higher ethanol production rate at 35°C than at 22°C the complexity of sugar did not seem to make a difference in ethanol production.  This could be because of the time constraints and not allowing the yeast and sugar to mix for a long enough period of time. Another reason could be not giving enough lag time.