Aipotu II Lab Report

Fermentation Lab Report
Hannah Newman

Fermentation is the chemical process converting sugar to gases and occurs in yeast and bacteria. In the experiment we conducted, we used sucrose and yeast and measured the fermentation carbon dioxide formation. The factors affecting fermentation that we tested in this experiment were temperature and the effect of a disinfectant. We measured the fermentation carbon dioxide formation by using a ruler and measuring the amount of bubbles in the tube that were formed. To conduct this experiment, we used 5 grams of sugar and 2 grams of yeast, but only used half of each for both experiments, so 2.5 grams of sugar and 1 gram of yeast for testing the effect of temperature and 2.5 grams of sugar and 1 gram of yeast for testing the effect of a disinfectant. We then mixed each beaker with 50 mL of water and stirred to fully dissolve the sugar and yeast. Then we used a 10 cc syringe and filled it up and put it in the fermentation tube and then added an additional 5 cc’s of the sugar/yeast solution to the tube. We then sealed the tube with a piece of parafilm and placed it into a water temperature of 10 degrees Celsius and recorded the time that we put them in. We then repeated that procedure but each time putting the tubes into 20, 30, 40, 50 and 60 degrees Celsius water. After 5-minute intervals, up to 20 minutes, we measured the amount of carbon dioxide formed in the fermentation tubes by using a ruler and measuring the amount of millimeters of carbon dioxide was produced. To test the variable of how a disinfectant affected the amount of fermentation, we repeated that procedure except instead of putting each fermentation tube into a certain temperature of water, we used the same temperature of water but each tube had a different amount of bleach in it. We put 0 drops of bleach in the first one and increased by 2 drops of bleach every tube, ending up with 10 drops in the sixth fermentation tube. We monitored the amount of fermentation, again with a ruler, every 5 minutes but only up to 15 minutes. What we found in this experiment was that fermentation occurred the most at about 50 degrees Celsius. There was 72 mm of carbon dioxide that we had measured at 50 degrees Celsius. We found that as the temperature got warmer, there was more fermentation until we hit 60 degrees Celsius and that dropped to 60 mm of fermentation. When we shared our results with other groups, they also said that fermentation occurred the most at 50 and 60 degrees Celsius for them.
When we experimented with the effect of the disinfectant, we mostly found that bleach kills the fermentation ability. We did conduct two trials of the experiment and found a dramatic difference, but my group and I think that we found what was the factor that affected that. In the first trial, we found the most fermentation with no bleach in the fermentation tube and the least fermentation with 8 drops in the tube, which we thought would happen in the tube with 10 drops. There was 74 mm of carbon dioxide in the tube with no bleach in it and the 1 mm of carbon dioxide in the tube with 10 mm of carbon dioxide. During our second trial, our results were so much different than the first. Again we found the most fermentation with no bleach and the least amount of fermentation in each tube with 2, 4, 6, and 8 drops of bleach and then 2 mm of fermentation in the tube with 10 drops. The reason that we believe the results were so much different was the height of the water level. We all noticed after we conducted the experiment and realized the measurements were a lot different that the water was much lower than the first experiment that we conducted and that lead us to think that’s why the results were so different.