SUGAR SUBSTITUTE EFFECT ON YEAST RESPIRATION By: Peter Szalay Grade 9 Central Catholic

Cell Respiration

Sucrose (C12H22o11) Disaccharide of glucose and fructose Linked via their anomeric carbons. Produced naturally in plants eg. Sugar cane or sugar beet. functions as an energy store for metabolism and as a carbon source for biosynthesis. Most common sweetener in the modern world

Sucralose (C12H19Cl3o8) Artificially created sweetener and is a sugar substitute Non-caloric due to the body not being able to metabolize it 1,000 times sweeter than sucrose

Saccharomyces cerevisiae (Bakers Yeast) Best known for alcohol fermentation and bread baking. Yeast is the most investigated cell in the world. Used in microbiology due to its ease of manipulation and rapid growth. Eukaryotic, shares biochemistry with more advanced organisms.

Purpose To investigate sucralose effect on yeast respiration. Hypotheses Alternate Hypothesis: The yeast will be able to metabolize sucralose yielding more CO2 than the control. Null Hypothesis: The yeast will not be able to metabolize the sucralose more than the control.

Materials Rapid Rise Saccharomyces cerevisiae, Red Star brand Micro Pipettes Macro Pipettes Balloons (9” Rounds) 125 ml Erlenmeyer Flasks Deionized Water Sucrose Sucralose 100mL Graduated Cylinders Plastic Tub Plastic Film Wrap

Procedure The Sucrose and sucralose were dissolved in sterile water at a concentrations of (10%). The sugar solutions were added to 5 flasks each in the ratios as seen below.  2.5 grams of Red Star rapid rise Cooking Yeast was added to each flask and balloons were immediately affixed to each flask. The flasks were transferred to a warm (35 C) water bath. After 60 minutes of incubation, each balloon was removed from the flask (careful to prevent any leakage of gas; each balloon was pinched at the neck and twisted off). A plastic tub was filled with water. Each graduated cylinder was filled with water to the brim and sealed with plastic wrap. The cylinder was inverted and immersed into the water and the plastic wrap removed. The balloon was placed into the water with the mouth placed into the cylinder.1 The mouth was slowly released and the air was pumped into the graduated cylinder.  The volume of gas was then recorded.

Solutions 0% Sugar 0.2% Sucrose 2% Sucrose 0.2% Sucralose 2% Sucralose Yeast 2.5g Sucrose Stock (10%) 0ml 0.8ml 8ml Sucralose stock (10%) Distilled Water 40ml 39.2ml 32ml Total Volume Solutions

Carbohydrate effect on Yeast Respiration P = 1.891 x 10–12

Dunnett’s test (Whole Set) Sugar Concentration Math T-value Conclusion (t-crit 3.48) 0.2% Sucralose 0.216 Not significant 2% Sucralose 0.993 0.2% Sucrose 1.273 Not Significant 2% Sucrose 15.494 Significant

Conclusions Fail to reject the null hypothesis Dunnett’s test showed that there was not a significant difference between the control and either of the tests of sucralose. Also, there was a significant difference between 0.20% sucrose and 0.20% sucralose, and a difference between 2% sucrose and 2% sucralose.

Limitations of project Slight variation in when data was recorded A larger sample size would be needed to get more accurate data. Not all the CO2 that was produced by the yeast rose into the balloon.

Extensions to the project The sugars can be tested for the survivorship of the yeast Other types of carbohydrates can be tested on their effects on yeast respiration. Other compounds such as honey can be tested for their effect on yeast as well Test for yeast cell population growth Test for other health factors in yeast

References Otterstedt, Karin et al. “Switching the mode of metabolism in the yeast Saccharomyces cerevisiae” EMBO reports vol. 5,5 (2004): 532-7. “Effect of Different Isomers of Sugar on Yeast Respiration.” California State University, Northridge, Nov. 2005, www.csun.edu/scied/2-longitudinal/schuster/index.html. “Basic Science: Understanding Experiments.” OpenLearn, The Open University, www.open.edu/openlearn/ocw/mod/oucontent/view.php?id=19988§ion=2.3. Libretexts. “Cellular Respiration.” Biology LibreTexts, Libretexts, 20 Feb. 2016, bio.libretexts.org/Ancillary_Materials/Experiments/General_Biology_Labs/Cellular_Respiration. Kayikci, Ömur and Jens Nielsen. “Glucose repression in Saccharomyces cerevisiae” FEMS yeast research vol. 15,6 (2015): fov068.

CO2 amount recorded 0% Sugar 0.2% Sucrose 2% Sucrose 0.2% Sucralose 8ml 21ml 125ml 13ml 22ml 24ml 128ml 14ml 23ml 15ml 27ml 155ml 17ml 28ml 186ml 18ml 30ml 195ml 19ml 25ml

ANOVA (Whole set) Summary of Data Treatments 0% 0.2% SR 2% SR 0.2% SL 2% SL Total N 5 5 5 5 5 25 ∑X 71 130 789 81 117 1188 Mean 14.2 26 157.8 16.2 23.4 47.52 ∑X2 1071 3430 128655 1339 2743 137238 Std.Dev. 3.9623 3.5355 32.2134 2.5884 1.1402 58.0173 Result Details Source SS df MS   Between-treatments 76488.64 4 19122.16 F = 89.03138 Within-treatments 4295.6 20 214.78   p=1.891 x 10–12 Total 80784.24 24    

ANOVA comparing 0.2% concentrations Summary of Data 0.2% SL 0.2% SR Total N 5 5 10 ∑X 81 130 211 Mean 16.2 26 21.1 ∑X2 1339 3430 4769 Std.Dev. 2.5884 3.5355 5.9339 Result Details Source SS df MS   Between-treatments 240.1 1 240.1 F = 25.01042 Within-treatments 76.8 8 9.6   p=0.00105 Total 316.9 9  

Anova comparing 2% concentrations Summary of Data Treatments 2% SR 2% SL 3 4 5 Total N 5 5 10 ∑X 789 117 906 Mean 157.8 23.4 90.6 ∑X2 128655 2743 131398 Std.Dev. 32.2134 1.1402 74.0228 Result Details Source SS df MS   Between-treatments 45158.4 1 45158.4 F = 86.92666 Within-treatments 4156 8 519.5   p=1.428 x 10-5 Total 49314.4 9