The Effect of Acidophilus on CO 2 Production in Yeast Gina Tripicchio Lauren Molier Marissa Evangelista Gina Tripicchio Lauren Molier Marissa Evangelista

Abstract / The purpose this experiment is to investigate the effect of acidophilus on CO 2 production in yeast. We combined yeast and varying amounts of acidophilus and measure CO 2 production. We were unable to conclusively find the amount of acidophilus that reduces CO 2 production in yeast. We were able to identify a trend in which 4 or more acidophilus tablets did reduce CO 2 production in most trials.

Introduction / This topic was chosen to investigate the effect of different amounts of acidophilus on the production of carbon dioxide in yeast. / Real life implications include: -the use of acidophilus while taking antibiotics -the use of acidophilus for yeast infections Independent Variable: Amount of acidophilus Dependent Variable: Amount of CO2 production Investigable Question: What is the effect of different amounts of acidophilus on CO 2 production in yeast? / This topic was chosen to investigate the effect of different amounts of acidophilus on the production of carbon dioxide in yeast. / Real life implications include: -the use of acidophilus while taking antibiotics -the use of acidophilus for yeast infections Independent Variable: Amount of acidophilus Dependent Variable: Amount of CO2 production Investigable Question: What is the effect of different amounts of acidophilus on CO 2 production in yeast?

Background Research / Lactobacillus acidophilus is a bacteria that produces lactic acid / It can be found in foods such as yogurt and sauerkraut / It protects the body against harmful bacteria including Candida albicans which causes yeast infections / Antibiotics kill probiotics such as acidophilus. Therefore, people taking antibiotics are at risk for developing yeast infections. / Taking acidophilus while taking and after completing antibiotics helps restore probiotics to the body and combats yeast infections / Yeast growth can be easily measured by CO 2 production / Lactobacillus acidophilus is a bacteria that produces lactic acid / It can be found in foods such as yogurt and sauerkraut / It protects the body against harmful bacteria including Candida albicans which causes yeast infections / Antibiotics kill probiotics such as acidophilus. Therefore, people taking antibiotics are at risk for developing yeast infections. / Taking acidophilus while taking and after completing antibiotics helps restore probiotics to the body and combats yeast infections / Yeast growth can be easily measured by CO 2 production

Hypothesis / If we increase the amount of Acidophilus, then the amount of CO 2 production will decrease because of the inhibition of fermentation

Materials List / 300mL of deionoized water / Plastic bottles (6 per trial) / Measuring spoons (1/2 teaspoon and 1 teaspoon) / Funnels / Glass beaker / Hot plate / Thermometer / Tape / Black pen / Camera / Acidophilus tablets / Dry yeast / Sugar / CO 2 probe / 300mL of deionoized water / Plastic bottles (6 per trial) / Measuring spoons (1/2 teaspoon and 1 teaspoon) / Funnels / Glass beaker / Hot plate / Thermometer / Tape / Black pen / Camera / Acidophilus tablets / Dry yeast / Sugar / CO 2 probe

Experimental Procedure / Control Group: First bottle in each trial group which did not contain any acidophilus / Experimental Group: Remaining five bottles in three trials which contained varying amounts of acidophilus, yeast, and water / Total # of Trial Groups: 4 / Control Group: First bottle in each trial group which did not contain any acidophilus / Experimental Group: Remaining five bottles in three trials which contained varying amounts of acidophilus, yeast, and water / Total # of Trial Groups: 4

Experimental Procedure / Step-by-step: / Step 1: (Trial 1) Line up six plastic bottles / Step 2: Add 1/2 tsp of sugar to bottle # 1 / Step 3: Add 1 tsp of yeast to bottle / Step 4: Lightly swirl bottle containing the dry ingredients to evenly mix the sugar and yeast / Step 5: Add 2 teaspoons of water to mixture / Step 6: Immediately insert CO 2 probe to measure and record CO 2 levels for 2 minutes / Step 7: After 2 minutes have passed, take out probe and set bottle aside / Step 8: Take remaining bottles (2-6) and repeat steps 2-7 but adding increasing amounts of acidophilus (starting with 1 tablet in bottle 2 and increasing to 5 tablets in bottle 6) after step 4 (Repeat for Trial groups 2, 3 and 4) / *Note* At the end of each trial, take a photo of the trial group to visually record the CO 2 production in each bottle. Then, at the end of the entire experiment, take picture of all trial groups lined up together for comparison purposes. / Step-by-step: / Step 1: (Trial 1) Line up six plastic bottles / Step 2: Add 1/2 tsp of sugar to bottle # 1 / Step 3: Add 1 tsp of yeast to bottle / Step 4: Lightly swirl bottle containing the dry ingredients to evenly mix the sugar and yeast / Step 5: Add 2 teaspoons of water to mixture / Step 6: Immediately insert CO 2 probe to measure and record CO 2 levels for 2 minutes / Step 7: After 2 minutes have passed, take out probe and set bottle aside / Step 8: Take remaining bottles (2-6) and repeat steps 2-7 but adding increasing amounts of acidophilus (starting with 1 tablet in bottle 2 and increasing to 5 tablets in bottle 6) after step 4 (Repeat for Trial groups 2, 3 and 4) / *Note* At the end of each trial, take a photo of the trial group to visually record the CO 2 production in each bottle. Then, at the end of the entire experiment, take picture of all trial groups lined up together for comparison purposes.

Results / Visual:

Results / Graphic: / Units- PPM (parts per million) / Graphic: / Units- PPM (parts per million)

Conclusion / Our evidence did not support our hypothesis that an increase in acidophilus would decrease CO 2 production in yeast / Our data was inconsistent and did not support one specific trend in acidophilus function / Our evidence did not support our hypothesis that an increase in acidophilus would decrease CO 2 production in yeast / Our data was inconsistent and did not support one specific trend in acidophilus function

Conclusion / Acidophilus is known to have an interaction with yeast, specifically in the body / In trials 1 and 2 there was a slight trend as predicted in our hypothesis but the increase/decrease was not significant / In trials 3 and 4, a new probe was used and we observed an unexpected trend in CO2 production / The amount of CO2 production increased in trials 1 through 3 and then decreased in trials 4 through 6. This suggests there could be a threshold for acidophilus function. / It also suggests there was a factor that contributed to the yeast growth that we did not predict / Acidophilus is known to have an interaction with yeast, specifically in the body / In trials 1 and 2 there was a slight trend as predicted in our hypothesis but the increase/decrease was not significant / In trials 3 and 4, a new probe was used and we observed an unexpected trend in CO2 production / The amount of CO2 production increased in trials 1 through 3 and then decreased in trials 4 through 6. This suggests there could be a threshold for acidophilus function. / It also suggests there was a factor that contributed to the yeast growth that we did not predict

Sources of Error / Our initial and most significant source of error was our CO2 probe. In trials 1 and 2 the probe did not function properly. In trials 3 and 4 a different probe was used but still did not function optimally / Another inconsistency was the technique used to mix the materials. They were not stirred but shaken and the materials might not have mixed as well / We did not activate the acidophilus before placing it in the bottle. The yeast was less dense and always settled on top. The yeast could have been more aggressive and competed with the acidophilus. This could have allowed the yeast to fully activate and inhibited the acidophilus / We regulated temperature as much as possible but yeast and acidophilus are both very temperature sensitive and a slight variation in temperature could have altered our results / Our initial and most significant source of error was our CO2 probe. In trials 1 and 2 the probe did not function properly. In trials 3 and 4 a different probe was used but still did not function optimally / Another inconsistency was the technique used to mix the materials. They were not stirred but shaken and the materials might not have mixed as well / We did not activate the acidophilus before placing it in the bottle. The yeast was less dense and always settled on top. The yeast could have been more aggressive and competed with the acidophilus. This could have allowed the yeast to fully activate and inhibited the acidophilus / We regulated temperature as much as possible but yeast and acidophilus are both very temperature sensitive and a slight variation in temperature could have altered our results

Further Questions to Investigate / What is the optimal dose of acidophilus to inhibit yeast growth? / How does temperature affect the function of yeast and acidophilus? / How do acidophilus and yeast compete for resources? / What is the optimal dose of acidophilus to inhibit yeast growth? / How does temperature affect the function of yeast and acidophilus? / How do acidophilus and yeast compete for resources?

Bibliography / Priya / NYHOS Microlab Manual / acidophilus.htm / Priya / NYHOS Microlab Manual / acidophilus.htm