Question

Ethanol is made by fermentation of a carbohydrate dissolved in water in the presence of yeast. The reaction is carried out at 30°C. Explain why the reaction is carried out at a temperature of 30°C rather than a temperature of 80°C.

A) 30°C promotes faster fermentation and better ethanol yield.
B) 80°C is too cold for the reaction to occur.
C) 30°C is optimal for the yeast's activity, while 80°C would kill the yeast.
D) 80°C would result in a higher ethanol concentration.

Answer 1

The fermentation process to produce ethanol is carried out at 30°C because it's the optimal temperature for yeast activity, which is responsible for the conversion of sugars to ethanol. Higher temperatures such as 80°C would kill the yeast, halting fermentation.

Step-by-step explanation:

The reaction to produce ethanol by fermentation is carried out at 30°C rather than at a higher temperature such as 80°C because 30°C is the optimal temperature for yeast activity. Yeast is a microorganism that plays a crucial role in fermentation. Higher temperatures like 80°C would be detrimental because they could kill the yeast, which is essential for the fermentation process. Fermentation involves a series of biochemical reactions, one of which includes pyruvate decarboxylase, a coenzyme derived from vitamin B1 (thiamine), which helps convert pyruvate to acetaldehyde. Then, acetaldehyde is further reduced to ethanol by the action of the enzyme alcohol dehydrogenase, while NADH is oxidized to NAD+ in the process. Thus, proper temperature control is essential to ensure that yeast survives and efficiently catalyzes the reaction, leading to the desired ethanol production.