Stirreer in stirred tank type bioreactor facilities

Options

A. Oxygen delivery from outside to inside
B. Mixing and aeration
C. Temperature control
D. Foam control

Answer

### Step-by-Step Text Solution:

1. **Understanding the Function of a Stirrer in a Bioreactor**:
- A stirred tank bioreactor is designed to facilitate biological reactions. The stirrer plays a crucial role in this process.

2. **Identifying the Main Functions of the Stirrer**:
- The stirrer serves two primary functions:
- **Mixing of Reactants**: It ensures that the reactants (nutrients, microorganisms, etc.) are uniformly mixed throughout the bioreactor. This is essential for a consistent reaction and optimal growth conditions.
- **Aeration**: The stirrer helps maintain adequate oxygen levels in the bioreactor. Oxygen is vital for aerobic processes, and the stirrer aids in distributing oxygen evenly throughout the liquid medium.

3. **Evaluating the Given Options**:
- The options provided are:
1. Oxygen delivery from outside to inside
2. Mixing and aeration
3. Temperature control
4. Foam control
- Based on the functions identified, the stirrer does not directly deliver oxygen from outside; rather, it helps in mixing and aerating the contents.

4. **Selecting the Correct Option**:
- The correct answer is **Mixing and aeration**. This option encompasses both the mixing of reactants and the maintenance of oxygen levels in the bioreactor.

5. **Conclusion**:
- In summary, the stirrer in a stirred tank bioreactor is primarily used for mixing the reactants and ensuring proper aeration, which is crucial for the success of the bioprocess.