The effect of water, sugar, and alcohol on yeast

The Effect of Water, Sugar, and Alcohol on Yeast

Abstract
Living organisms require energy to sustain their daily activities. As a living organism, Yeast is a bacteria that is actively used in the fermentation processes such as when baking or brewing alcohol, and for this process to take place, it requires sugar as its source of energy (Sahlström, Park & Shelton, 2004). Depending of the concentration of sugars used the yeast reactions tend to vary. In this study, the idea is to understand how simple organisms such as Yeast are affected by different pollutants, in this case water, sugar and Alcohol. The experiment involved the use of two fermentation tubes to test yeast reactions when under the influence of different pollutants. From the results obtained, the fermentation process appeared to take faster when yeast was used in a baking solution and slowest when used to make Vinegar. In addition, adding sugar to yeast yielded the highest result because sugar is source of energy during the fermentation process.

Introduction
Living things are able to perform their daily activities by obtaining energy through the process of cellular respiration. During this process, energy in form of Adenosine Triphosphate (ATP) is produced. Cellular respiration is important for organism because without it they wouldn’t be able to survive, or they wouldn’t have ATP to function (Polakowski, 2008). The study purposes to understand how pollutants would affect a simple organism such as Yeast. In this case, a simple organism refers to any living organism with only one cell. Yeast is a eukaryotic that is single-celled and belongs to the kingdom fungus (Sahlström, Park & Shelton, 2004). In this research, we discovered that the pollutants dose effect the simple organism. To clarify, the alcohol and sugar used in the experiment are pollutants that affect the yeast in different ways either as catalyst or an inhibitor to the fermentation process. The hypothesis for this experiment is that when the yeast has carbohydrate the rate of cellular respiration increases and vice versa.

Materials and Method
The materials used for this experiment included two fermentation tubes whose main purpose was to use them to store the pollutants that would be tested in this experiment. One of the fermentation tubes had the carbohydrate source while the second was without a carbohydrate source. Other materials necessary to make this experiment a success included; at least 5 mL yeast which was to be used throughout the experiment, 3 mL of sugar and 50 mL of warm water. In addition, vinegar, bleach solution, Isopropyl alcohol, salt solution and baking powder solution were also used.
The procedure involved carrying out this experiment involved first setting up the different fermentation tubes. In the first tube, we had to mix 1.25 mL yeast with 13 mL warm water in 25 mL beaker, and label it as tuber number 1. After that, for tuber number 2, we had to mix 1.25 mL of yeast with 1.25 mL sugar in 25mL beaker. The mixtures were then stirred gently and left for about 10 minutes to allow for the process of fermentation to take place. Observations were then made and recorded for further analysis. To test how yeast would react with different impurities, different tubes each containing , vinegar, bleach solution, Isopropyl alcohol, salt solution and baking powder solution were set up and a 1.25 mL of yeast solution put in each of them. The amount of carbon dioxide emitted from these reactions was then recorded.

Results
From the observations made in this experiment, we noticed that over a period of about 10 minutes, the mixture between yeast and water had produced 4.6 mL of carbon dioxide as a byproduct of the fermentation process. On the other hand, the mixture between yeast, sugar and water yielded 13 mL of carbon dioxide over a ten minutes period. With the other mixtures, the volume of carbon dioxide emitted was lower with vinegar recording the lowest, followed by bleach solution, Isopropyl alcohol, and salt solution with baking solution being the highest in this group. The data on the amount of carbon dioxide emitted when yeast was mixed with different solutions is displayed below

Gas Volume (mL)
Contents / Time (min) 0 1 2 3 4 5 6 7 8 9 10
1 Yeast/ Water 2 3 3.5 3.6 3.8 4 4 4.1 4.3 4.5 4.6
2 Yeast/ Sugar solution 1.5 1.9 5.3 5.5 8 9 11 13 13 13 13
3 Yeast/ Vinegar 0 0 0 0 0 0 0 0 0 0 0
4 Yeast/ Salt Solution 0 1 1.6 2.9 3.1 3.5 4 4.6 4.9 5.5 5.6
5 Yeast/ Baking solution 0 0.5 0.7 1.5 2 3 3.8 4.5 5 5.4 5.8
6 Yeast/ Bleach Solution 0 0.5 0.4 0.3 0.2 0.3 0.7 1.2 1.5 2.4 3.4

The information collected in this experiment was presented graphically as shown in the figure below.

DISCUSSION:
The mixture between yeast and water produced 4.6 mL of carbon dioxide within a 10 minutes period, while that of yeast, sugar, and water produced 13 mL of carbon dioxide in the same amount of time. This observation implies that sugar has a strong effect on the fermentation process and for this reason it can be regarded as a catalyst which fastens the process. Other impurities that were added to the yeast solution did not yield the same amount of carbon dioxide as sugar and water did, which means that they contributed to the speeding up of the of the yeast reaction, their impact was not significant. In the case of Vinegar, there was no amount of carbon dioxide which was produced and this implied that the rate of cellular respiration was not affected by its presence and therefore it is not a carbohydrate.
The graphical representation above shows how different solutions reacted with yeast, and it is evident that there was a fast reaction in the first few minutes and it subsidized gradually with time. The steep slope is an indication of the rate of reaction between yeast and the different impurities where a steep slope indicates a fast reaction while a gentle slope indicates a slow reaction (Barnett, & Entian, 2005). This outcome can be explained that yeast was actively reacting with the impurities in the first few minutes because that was when it had first made contact with each other. However, this reaction subsided because the surface areas in contact with the impurities had already reacted.

Conclusion
From the foregoing, pollutants affect simple living organisms like yeast in different ways either as catalyst or an inhibitor to the fermentation process. This experiment was able to prove that when yeast is mixed with carbohydrate solutions such as sugar, the rate of cellular respiration increases because they act as a catalyst to the fermentation process. On the other hand, non-carbohydrates such as Vinegar affect yeast negatively in the sense that they inhibit the fermentation process which explains why there was no amount of carbon dioxide produced when yeast was mixed with vinegar. For this reason, we can conclude that depending on the concentration of sugars or carbohydrates used the yeast reactions tend to vary.

References
Polakowski,, T. M. (2008). THE EFFECT OF DIFFERENT SUGARS ON THE RATE OF FERMENTATION IN YEAST. Ohio Journal of Science, 108(1), 30-36.
Barnett, J. A., & Entian, K. (2005). A history of research on yeasts 9: Regulation of sugar metabolism. Yeast, 22(11), 835-894. doi:10.1002/yea.1249
Sahlström, S., Park, W., & Shelton, D. R. (2004). Factors Influencing Yeast Fermentation and the Effect of LMW Sugars and Yeast Fermentation on Hearth Bread Quality. Cereal Chemistry Journal, 81(3), 328-335. doi:10.1094/cchem.2004.81.3.328