The Effect of pH and Time on Aerobic CO2 Production in S. cerevisiae


  • Mahta Yaghoubi-Hargalan


This experiment sets out to find the effect of pH and time on aerobic respiration in Saccharomyces
cerevisiae blooming in different pH treatments. S. cerevisiae were added to four bottles with different pH
mediums – a pH of 2, 4, 8 and a control (pH 7). Balloons attached to the bottles would collect the CO2 gas
released by the yeast, and the balloon height would be considered a measure of respiration. Data was
collected in two intervals separated by an hour to measure the effect of time. Yeast in the control (pH 7)
had significantly greater aerobic respiration compared to the other pH groups (p < 0.0001). Only the yeast
in the control (pH 7) group showed a significant increase in respiration with time (p < 0.0001), while the
rest showed no change with time. These results are discordant with what is known in studies conducted
for anaerobic respiration. Consequently, this suggests that the baking industry (which focuses on aerobic
respiration) should follow different guidelines for the usage of yeast than the liquor industry (which focuses
on anaerobic respiration) in order to maximize profit