Why disc-stack centrifuges are preferred in bioseparations: Which feature most strongly explains their widespread use for continuous clarification of cell broths?

Introduction:
Choosing a centrifuge for bioprocessing involves balancing throughput, solids handling, shear, and cleaning. Disc-stack (disc centrifuge) machines are often selected for harvest and clarification steps. This question focuses on the single most decisive advantage in typical bioseparation lines.

Given Data / Assumptions:

• Feed: cell suspensions at moderate solids volume fraction.
• Requirement: continuous, steady processing in upstream/downstream integration.
• Objective: minimize tanks and hold times while maintaining clarity.

Concept / Approach:
Disc-stack centrifuges provide high clarification area per footprint using conical discs and can operate continuously with intermittent or continuous solids discharge. Their steady, high-throughput operation integrates well with continuous fermentation or perfusion and reduces surge capacity needs.

Step-by-Step Solution:
Identify needed feature: continuous feed/effluent with solids ejection.Compare with batch devices: tubular bowl often requires batch solids removal.Conclude disc-stack's continuous mode is the primary advantage in practice.

Verification / Alternative check:
Process schematics show disc-stack units feeding directly into downstream steps (e.g., depth filtration) without long hold-ups, highlighting the benefit of continuous operation.

Why Other Options Are Wrong:
Lower cost: disc-stacks are not always the cheapest; costs vary with capacity and features.

Higher speed: some other designs can reach similar or higher g-forces; speed alone is not the reason.

Easiest to operate: they require skilled setup (nozzle settings, sludge handling); “ease” is not universal.

Common Pitfalls:

• Overemphasizing g-force without considering residence time distribution and solids handling.
• Ignoring cleaning and sanitary design requirements that accompany continuous operation.

Final Answer:
Continuous operation with steady feed and discharge capabilities