Bioreactors have

Options

A. Foam control system, temperature control system
B. Oxygen delivery system
C. pH control system
D. All the above

Answer

To solve the question "Bioreactors have," we will analyze the options provided and determine which systems are essential for the functioning of bioreactors.

### Step-by-Step Solution:

1. **Understanding Bioreactors**:
- Bioreactors are vessels where biological products are produced using microorganisms, plant cells, or animal cells. They provide a controlled environment for the growth of these cells.

2. **Identifying the Requirements**:
- For effective growth and productivity in bioreactors, several control systems are necessary:
- **Foam Control System**: This system manages the foam that can form during fermentation processes, ensuring that it does not interfere with the operation.
- **Temperature Control System**: Maintaining the right temperature is crucial for optimal growth and metabolic activity of the cells.
- **Oxygen Delivery System**: If the process is aerobic, adequate oxygen supply is essential for the respiration of the microorganisms or cells.
- **pH Control System**: The pH level must be maintained within a specific range to ensure that the biological processes occur efficiently.

3. **Evaluating the Options**:
- **Option A**: Foam control system - Necessary.
- **Option B**: Temperature control system - Necessary.
- **Option C**: Oxygen delivery system - Necessary for aerobic processes.
- **Option D**: pH control system - Necessary.
- **Option E**: All of the above - Since all the mentioned systems are essential for the operation of bioreactors, this option is correct.

4. **Conclusion**:
- Based on the analysis, the correct answer is **Option D: All of the above**. Bioreactors indeed require foam control systems, temperature control systems, oxygen delivery systems, and pH control systems to function effectively.