Monod Chemostat Microbial Growth Kinetics Calculator

A chemostat is a continuous culture bioreactor where fresh sterile nutrient medium is fed at a constant flow rate while culture broth is continuously removed.

In steady-state operation, the specific growth rate mu adjusts automatically to equal the dilution rate D.

When D < D_crit, the system reaches self-regulating steady state where cell reproduction matches dilution washout.

Residual substrate concentration S_bar depends solely on kinetic parameters (mu_max, Ks) and dilution rate, independent of feed concentration.

If dilution rate exceeds D_crit, cells are washed out faster than they can reproduce, leading to total biomass collapse.

Steady-state biomass (g/L) represents cell density maintained in continuous production.

Volumetric productivity (g/(L*h)) indicates harvest rate of biomass per unit reactor volume.

Operating near 0.8 * D_crit typically maximizes volumetric biomass production.

• Dilution rate D: Increasing D decreases steady-state biomass but increases biomass productivity up to an optimal peak.
• Inlet substrate Sin: Higher feed concentration directly increases steady-state biomass without altering residual substrate S_bar.
• Cell maintenance energy: At very low dilution rates, non-growth maintenance respiration reduces actual biomass yield.

• Industrial fermentation design for single-cell proteins, recombinant proteins, and biopharmaceuticals.
• Optimizing continuous wastewater biological treatment and activated sludge processes.

• Assumes ideal sterile feed without incoming cells and complete liquid mixing in the vessel.
• Assumes zero endogenous cell decay and single substrate limitation.