Fed-Batch Exponential Feed Calculator
Bioprocess optimization & recombinant protein expression: Calculate exponential feeding trajectories F(t), broth volume expansion, and oxygen uptake over time.
Initial Fed-Batch Conditions
Feeding Dynamics & Final Yield
Recommended Tools & Equipment
Tested hardware and components for high reliability
Frequently Asked Questions
Why is an exponential feed profile used in fed-batch fermentation?
In aerobic cultures (e.g. E. coli or Pichia pastoris), high sugar concentrations trigger overflow metabolism (Crabtree effect), converting sugar into inhibitory acetate or ethanol. By exponentially feeding substrate to exactly match cell consumption at a set specific growth rate (µ < µ_crit), the substrate concentration remains near zero while biomass accumulates to ultra-high densities.
How does feed substrate concentration (S_feed) affect volume expansion?
Using a highly concentrated feed (e.g. 500 to 700 g/L glucose) delivers the required carbon mass in minimal liquid volume. Dilute feeds add excessive water, causing the bioreactor to fill up prematurely before achieving target cell densities.
What happens if the actual specific growth rate exceeds µ_crit?
When growth rate surpasses the critical threshold µ_crit (typically ~0.20 to 0.25 h⁻¹ for E. coli), the respiratory tricarboxylic acid (TCA) cycle saturates. Cells spill carbon into acetate excretion, which lowers broth pH, inhibits further cell growth, and drastically impairs recombinant protein folding.