Q.27 Fed batch cultivation is suitable for which of the following?
P. Processes with substrate inhibition
Q. Processes with product inhibition
R. High cell density cultivation
(A) P and Q only (B) P and R only (C) Q and R only (D) P, Q and R

Fed-batch cultivation excels in bioprocess engineering by addressing key limitations of batch systems through controlled nutrient feeding. This technique proves suitable for processes facing substrate inhibition and high cell density needs, making option (B) P and R the correct answer.​

Correct Answer

The right choice is (B) P and R only. Fed-batch mode prevents toxic substrate buildup via gradual feeding while enabling dense biomass accumulation, unlike batch or continuous systems.​

Option P: Substrate Inhibition

Fed-batch cultivation effectively mitigates substrate inhibition by maintaining low, non-toxic substrate levels through controlled feeding rates, such as exponential or linear addition matching consumption.​
High initial substrate loads in batch cultures halt growth, but fed-batch ensures optimal concentrations for maximum productivity in processes like microbial fermentation.​

Option Q: Product Inhibition

Fed-batch struggles with product inhibition since the product accumulates without removal, potentially reaching inhibitory levels despite substrate control.​
Techniques like perfusion suit such cases better, as fed-batch cannot dilute or extract intracellular/extracellular inhibitors effectively.​

Option R: High Cell Density

This method shines for high cell density cultivation by sustaining prolonged growth phases with nutrient feeds, achieving titers far beyond batch limits (e.g., >100 g/L dry cell weight).​
Common in antibody production and yeast fermentation, it maximizes volumetric productivity without dilution from continuous harvest.​