Continuous cultures (chemostats) in industry: which statement is NOT correct regarding their uses and risks?

Introduction / Context:
Continuous cultures (chemostats, turbidostats) maintain cells at steady state by balancing growth with dilution. They are powerful for research and some industrial processes, but adoption varies depending on regulatory and operational constraints.

Given Data / Assumptions:

• Industry practice differentiates commodity processes and strictly regulated biopharma manufacturing.
• Contamination control and genetic stability are crucial in long duration runs.
• Batch and fed-batch remain dominant for many pharmaceuticals due to validation simplicity.

Concept / Approach:
Wastewater treatment widely uses continuous flow with recycle (activated sludge), fitting option A. Long-running chemostats face contamination and mutant takeover risks, supporting option B. Continuous operation reduces turnaround downtime, supporting option D. In contrast, broad adoption for pharmaceuticals has historically favored batch/fed-batch because validation, containment, and lot release are simpler; while continuous bioprocessing is emerging, it is not accurately described as “very useful” in the sense of being widely adopted across pharma manufacturing.

Step-by-Step Solution:
Match known applications: wastewater treatment → continuous.Assess risks: mutation/contamination → major concerns in long runs.Operational uptime: continuous reduces cleaning frequency.Pharma adoption: still limited/targeted compared with batch/fed-batch dominance; therefore, this claim is not correct.

Verification / Alternative check:
Industry surveys and regulatory guidance consistently show fed-batch leading in biologics; continuous is growing but not yet the norm for final drug substance manufacture.

Why Other Options Are Wrong:
A, B, and D correctly reflect typical practice and constraints.

Common Pitfalls:
Equating research utility with broad GMP adoption; underestimating contamination control and validation challenges for multi-month chemostats.

Final Answer:
They are very useful and widely adopted for pharmaceutical production