Process control in bioreactors: Which feeding strategy helps prevent excessive lactate generation in mammalian cell culture?

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:

• Lactate primarily arises from glucose catabolism via glycolysis.
• Glutamine catabolism produces ammonium, a different inhibitory metabolite.
• Objective is to minimize lactate buildup without starving cells.

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).