Which of the folliowing statements is not trur for stirred tank fermentation

Options

A. Buffer needed to control
B. Buffer and feed possible
C. Control dissolved oxygen
D. Easy in process sampling

Answer

**Step-by-Step Solution:**

1. **Understanding Stirred Tank Fermentation:**
- Stirred tank fermentation is a process that occurs in bioreactors known as stirred tanks. These are large vessels designed to facilitate the growth of microorganisms for the production of biochemical substances.

2. **Key Features of Stirred Tank Fermentation:**
- In stirred tank fermentation, there is constant stirring. This stirring is crucial as it ensures that nutrients and oxygen are evenly distributed throughout the tank, allowing all living cells to access the necessary resources for growth.

3. **Evaluating the Statements:**
- The question asks which statement is not true regarding stirred tank fermentation. We will evaluate each option provided.

4. **Option Analysis:**
- **Option 1: Buffer needed to control pH.**
- This statement is true. Buffers are indeed necessary to maintain the pH levels in the fermentation process.
- **Option 2: Buffer and feed possible.**
- This statement is also true. Buffers and feeding of nutrients are integral to the fermentation process.
- **Option 3: Control dissolved oxygen.**
- This statement is misleading. While controlling dissolved oxygen is important in fermentation, in stirred tank fermentation, oxygen supply is generally abundant due to constant stirring, which allows for sufficient oxygen transfer. Thus, this statement can be considered not true in the context of the question.
- **Option 4: Easy in-process sampling.**
- This statement is true. Stirred tank fermenters are designed to allow for easy sampling during the fermentation process.

5. **Conclusion:**
- Based on the evaluation, the statement that is not true for stirred tank fermentation is "Control dissolved oxygen" because the process typically ensures an abundant supply of oxygen due to constant stirring.

**Final Answer:**
- The statement that is not true for stirred tank fermentation is: "Control dissolved oxygen."

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