ANS:C - 30 to 50

Very dilute solutions are generally used in fermentation reactions for which the optimum temperature range is 30 to 50 °C for several reasons:

1. Microbial Activity:

• Optimal Growth: This temperature range promotes the optimal growth and metabolic activity of fermentation microorganisms, such as yeast and bacteria, enhancing the efficiency of the fermentation process.

2. Product Yield:

• Maximized Production: Maintaining temperatures within this range helps maximize the yield of desired fermentation products, such as alcohol or organic acids, by optimizing microbial performance.

3. Preventing Inhibition:

• Avoiding Inhibitory Effects: At temperatures below 30 °C, microbial activity may be too slow, while temperatures above 50 °C can inhibit microbial growth or denature enzymes, leading to reduced fermentation efficiency.

4. Dilute Solutions:

• Enhanced Mass Transfer: Using very dilute solutions increases the solubility and availability of substrates for microbial consumption, promoting better fermentation outcomes and reducing the risk of product inhibition.

5. Process Control:

• Easier Temperature Regulation: Working within this temperature range allows for more straightforward temperature control during fermentation processes, facilitating consistent and reliable results.

Summary:

In summary, very dilute solutions are used in fermentation reactions at temperatures of 30 to 50 °C because this range supports optimal microbial activity, maximizes product yield, prevents inhibitory effects, enhances mass transfer, and simplifies temperature regulation, all of which are crucial for successful fermentation.