87. A mechanically agitated bioreactor for an aerobic microbial process can be scaled up from pilot
plant data to commercial plant on the basis of
1. equal impeller size
2. equal inoculum size
3. equal power/unit volume
4. equal air bubble size

 

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Scaling Up a Mechanically Agitated Bioreactor

Scaling up a mechanically agitated bioreactor from pilot plant data to a commercial plant involves transferring the operating conditions and efficiency from a small-scale system to a large-scale system. The goal is to ensure that the microbial processes, such as oxygen transfer and mixing, are maintained effectively in the larger system.

Factors for Scaling Up Bioreactors

When scaling up a mechanically agitated bioreactor for aerobic microbial processes, the key parameter that is typically considered is equal power/unit volume. Here’s why:

• Equal Impeller Size: The size of the impeller may need to be adjusted based on the scale of the reactor. Larger reactors typically require larger impellers for efficient mixing, making this factor less directly relevant to scaling up.

• Equal Inoculum Size: While the size of the inoculum is important for the initial growth of microorganisms, it is typically controlled independently based on the desired concentration and not scaled directly from pilot plant to commercial plant.

• Equal Power/Unit Volume: This is the most relevant factor when scaling up a bioreactor. Ensuring that the power per unit volume remains constant helps maintain similar mixing and aeration conditions, which are critical for efficient microbial growth and product formation in larger systems.

• Equal Air Bubble Size: Air bubble size is influenced by the design of the aeration system and not necessarily scaled uniformly from pilot to commercial systems. Bubble size can vary depending on factors like the aerator design and gas flow rate.

Correct Answer: Option 3

The correct answer is Option 3: Equal power/unit volume.

Explanation:

To scale up a bioreactor effectively, it is important to maintain the same power input per unit volume to ensure that the mixing, oxygen transfer, and microbial growth conditions are similar between the pilot and commercial systems. This ensures that the system operates efficiently at a larger scale.

Conclusion

Scaling up a bioreactor for aerobic microbial processes requires careful consideration of various operational parameters. By focusing on equal power/unit volume, it is possible to maintain the efficiency of the system and ensure a smooth transition from pilot to commercial plant. This approach helps achieve consistent performance and product yield at the larger scale.