Question

What are important products of yeast fermentation?
A. Ethanol and acetic acid
B. Butanol and glycerol
C. Phenethyl alcohol, amyl alcohol and caproic acid
D. All of the above

Answer 1

Hint: Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. According to biochemistry it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen.

Complete answer:
In yeasts, fermentation there is the production of ethanol and carbon dioxide which can be used in food processing: Bread – Carbon dioxide causes dough to rise (leavening), the ethanol evaporates during baking. By fermentation, the yeast species Saccharomyces cerevisiae converts carbohydrates to carbon dioxide, acetic acid and alcohols like ethanol, butanol, phenethyl and amyl alcohol.The fermentation of yeast takes 12 to 36 hours for its fermentation. There are certain conditions needed for the yeast fermentation like food, moisture and a controlled warm environment. Its byproducts from consuming food are the gas carbon dioxide, alcohol, and other organic compounds. These yeast cells gain some energy from the conversion of the sugar into carbon dioxide and alcohol. Alcohol is the other by-product of fermentation. Alcohol remains in the liquid which is very great for making an alcoholic beverage but not for the yeast cells, as the yeast dies when the alcohol exceeds its tolerance level. When fermentation is almost completed, most of the yeast will settle down to the bottom of the fermenter. The bottom of the fermenter is shaped like a cone, which makes it easy to capture and remove the yeast, which is saved and used in the next batch of beer.When fermentation has finished, the beer is cooled to about 32 F (0 C).

Hence the correct answer is OPTION(D)

Note: Yeast is an organism that ferments. When yeast ferments sugar, the yeast uses sugar and produces alcohol. Fermentation is a less efficient form of respiration than oxidative respiration (respiration using oxygen). The ethyl alcohol produced by yeast is used to make beverages or biofuel.