Downstream processing — timing of vitamin recovery in fermentation In an industrial vitamin fermentation, the product recovery step from the broth is typically scheduled prior to which of the following process steps to protect yield and quality?

Introduction / Context:
Downstream processing (DSP) determines overall process economics and product integrity in vitamin fermentations. The order of operations matters: some unit operations risk degrading vitamins or complicating separations, so recovery is planned to maximize stability and purity.

Given Data / Assumptions:

• Many vitamins are sensitive to pH, temperature, and enzymatic attack.
• Autolysis releases intracellular enzymes and breakdown products that can degrade vitamins and foul DSP equipment.
• Industrial processes often clarify and extract the vitamin prior to steps that increase impurity loads.

Concept / Approach:
Autolysis (intentional or incidental) ruptures cells, liberating proteases, nucleases, and oxidative enzymes that can reduce product stability and complicate purification. Therefore, efficient recovery (for example, adsorption, extraction, precipitation) is usually executed before substantial autolysis. While acidification or alcohol treatment may be used as controlled DSP tools, proceeding to extensive autolysis prior to recovery is commonly avoided.

Step-by-Step Solution:
Identify the sequence risk: autolysis creates degradative conditions for vitamins.Prioritize recovery to isolate and stabilize the vitamin before autolysis proceeds.Select “Autolysis of cells” as the step that should follow, not precede, recovery.

Verification / Alternative check:
Process flow diagrams for riboflavin, cobalamin, and other vitamins show timely separation, adsorption, or extraction before prolonged cell lysis to protect yield.

Why Other Options Are Wrong:
Acidification and alcohol treatment can be controlled DSP steps within validated ranges; “none” ignores the real risk posed by autolysis; carbon polishing is typically a late-stage purification after initial recovery, not a scheduling hazard.

Common Pitfalls:
Allowing storage delays that encourage autolysis; not inactivating cells/enzymes when required; failing to adjust pH and temperature to stabilize the vitamin during hold times.

Final Answer:
Autolysis of cells.