Sugar Fermentation

Methods: An observation was made on whether or not the sugars, fructose and ribose would be fermented in yeast (Saccharomyces cerevisiae). By looking at the chemical structures of these sugars given in (Figure 1), we looked for anything that might determine the metabolization of these sugars. An equal 6mL (milliliter) sample of 2.5% fructose and yeast suspension was pipetted into a fermentation tube. The same procedure above was performed with the sugar ribose which has a concentration of 2.5% as well. Once this was done, the tubes were turned upside down to remove any air bubbles formed. Both tubes were then incubated in a 37◦ C (Celsius) water bath for ten minutes. After ten minutes, both tubes were taken from the water bath and observed for any presence of gas accumulation. This accumulation could be observed in the vertical stem of the tube and would look like frothy bubbles, also known as CO2 (Carbon dioxide). The results were documented and a hypothesis was made based on these results that may provide an explanation for the observations made on the structures of fructose and ribose. Next we tested two different sugars that we picked from a list of six sugars given in our lab manual, (arbabinose, galactose, mannose, sorbose, glucose, and xylose). The chemical structures for these sugars were also given (see Figure 2). Based on the structure of the sugar we chose one that we thought would metabolize in yeast and one we expected not to. We tested these sugars the same way that fructose and ribose were tested in the previous procedures. The predictions and results for the two sugars were documented in our notebook. We then looked back at our first hypothesis. If our first hypothesis did not support our results, we revised it and proposed a new hypothesis. The new hypothesis considered another feature of the sugar structure that might be important to the metabolization. We continued to test the rest of the sugars, two at a time in order to see