Ah Sugar Sugar: The Effect of Disaccharides on Yeast Ethanol Production

Abstract

Carbohydrates are classified as monosaccharides (one unit sugar), disaccharides (two unit sugar) and other complex sugars. We used the disaccharides sucrose and maltose to measure the ethanol production of baker’s yeast. When yeast consumes sugar, it undergoes fermentation and produces ethanol during the glycolysis stage of cellular respiration. We hypothesized that maltose would result in a higher ethanol production rate than sucrose, due to maltose’s two glucose molecule composition compared to sucrose’s composition of one glucose and one fructose. We ran 18, five-minute trials testing each sugar nine times. Our results revealed that the variance for ethanol production levels for sucrose and maltose were equal. Therefore, our hypothesis was not supported. While ethanol manufactures could use either sucrose or maltose to produce ethanol, we suggest they use sucrose because of the cheaper difference in cost in comparison to maltose.