Question

2. Is there a difference between the fermentation rate of the yeast and the top the fermentation rate of the yeast and the temperature? Why? 3. Why do you need to incubate the yeast before you start monitoring air pressure? 4. What else do you think is being produced by yeast fermentation besides CO2? 5. Could you use a pressure sensor to measure aerobic respiration in yeast? Why?

Answer 1

2.The value of yeast growth coefficient and fermentation coefficientis strongly influenced by temperature. The fermentation coefficient increases steadily unto 40°c, after it falls away steeply. The growth coefficient increases steadily upto 30°c after which it increases only slightly upto 36.c. The optimal fermentation temperature of traditional brewing yeast is 28-33°C 3. The yeast was probably engaged in aerobic respiration prior the experiment, since it is more efficient than anaerobic respiration. After a layer of vegetable oil is placed on the surface of the yeast and sugar solution, it is necessary to incubate the mixture in order for anaerobic respiration to commence. Once the anaerobic respiration begins as a result of incubation, carbon dioxide levels will begin to increase, and will be measurable as heightened air pressure. 4. The yeast needs to begin to metabolize the sugar before you can start measuring the CO2 produced. Incubating it gives the yeast the energy that it needs to begin metabolizing the sugar.

5. Ethanol fermentation produces unharvested byproducts such as heat, food for livestock, water, methanol, fuels, fertilizer and alcohols. The cereal unfermented solid residues from the fermentation process, which can be used as livestock feed or in the production of biogas are referred to as Distillers grains. 6. We couldn't use a gas pressure sensor because when the yeast respire aerobically, oxygen gas is consumed at the same rate that co2 is produced