Difficulty: Medium
Correct Answer: Maintain low glucose concentration (controlled feed)
Explanation:
Introduction / Context:
In fed-batch mammalian cultures, excessive glycolytic flux leads to lactate accumulation, which harms growth and productivity. Process engineers therefore modulate substrate feeds to steer metabolism.
Given Data / Assumptions:
Concept / Approach:
Keeping extracellular glucose at modest levels (for example, 0.5–2 g/L) reduces overflow metabolism and favors oxidative pathways. Feedback-controlled feeding maintains steady, lower glucose concentrations, decreasing lactate formation while sustaining growth.
Step-by-Step Solution:
Verification / Alternative check:
Publications and industrial guidelines show lactate reduction when glucose is maintained at low, non-saturating levels, often combined with pH/base control and alternative carbon sources.
Why Other Options Are Wrong:
Common Pitfalls:
Over-restricting glucose so cells starve; controlled feeding should sustain but not saturate.
Final Answer:
Maintain low glucose concentration (controlled feed).
Discussion & Comments