Factors Affecting Fermentation of Glucose by Yeast
At the end of the day alcohol and carbon dioxide are the end products when yeast is used in the fermentation procedure. But end products like acetic acid or lactic acid can also be gained depending on the circumstances.
The salinity, air conditions, temperature, pH of the system, the enzyme systems of microorganisms, and the type of sugars being fermented can show a variety in the type of end products produced. In this study the tube with the highest amount of chlorine is added, an increase in the rate of fermentation should be observed. Methods and Materials: 100ml of the stock solution of 10% glucose was placed into four separate beakers. Each beaker was labeled “1 (control),” “2 (5 drops),” “3 (10 drops),” and “4 (15 drops)”.
Five drops of 6% sodium hypochlorite was added to beaker #2, 10 drops to beaker #3, and 15 drops to beaker #4. The contents of the yeast suspension were then stirred thoroughly to be sure the yeast cells were suspended and not settled at the bottom and to each solution 50ml of the yeast suspension was added. The contents of each beaker were stirred with a glass stirring rod to mix the solutions thoroughly. Each of the four fermentation tube bowls were filled with one of the solutions and the tubes were tilted so that the vertical arm was full, but the bowl was nearly empty.
Each fermentation tube was labeled in order to indicate its contents. The tubes were placed in a warm place (in an incubator or near a heat lamp). Every 10 minutes for 90 minutes a measurement was made and the amount of gas produced in each of the four fermentation tubes was recorded and graphed. Results: Figure 1 As shown in figure 1, this study revealed that when chlorine was added there was a decline in the fermentation tubes excluding group “two,” the five drop tube. Therefore this observation concluded that when there’s a large amount of chlorine the fermentation rate slowed down.
But when there was a little amount of chlorine there was increase in the rate of fermentation. An average of about 15 additional minutes were spared in order to equal the amount of fermentation in the control tube and five drop tube when large amounts of chlorine were evident. Discussion: All four beakers were evaporated by the 60 minute mark. The solution with five drops was the first to completely evaporate, following with the control group, the 10 drops and finally the 15 drops.
No real conclusions could be drawn from this study because of the order in which the evaporation was completed. This lab also generates questions that could not have been asked before the lab. Why do some fermentation tubes have all their solution evaporate and not others? What would have happened if more yeast solution were added to the fermentation tubes? With the information discovered, experimenters know some of the different factors affecting fermentation of glucose by yeast. This information will help alcoholic fermentation in the wine and beer industries.