ADVANCED YEAST GROWTH CALCULATOR - ETHANOL FERMENTATION

The specific growth rate (μ, in h⁻¹) of Saccharomyces cerevisiae can be modeled during ethanol fermentation by integrating various yeast growth kinetic equations. Fundamentally these models are mostly based on modified Monod equation and can account for substrate limitation and be extended to include inhibition terms accounting for substrate (glucose), product (ethanol), pH deviations, and temperature extremes impact on yeast growth. These models are unstructured and unsegregated, treating the yeast population as uniform and focused on key environmental factors. Overall yeast growth equation is composed of individual function models derived from mass balance equations for batch or fed-batch systems, where growth is linked to substrate consumption and product formation. The general form integrates multiplicative factors:

μ = μ_max⋅f(S)⋅g(P)⋅i(pH)⋅h(T)

μmax : Maximum specific growth rate under optimal conditions (typically 0.4–0.6 h⁻¹ for S. cerevisiae in ethanol fermentation).
S : Glucose concentration (g/L, substrate).
P : Ethanol concentration (g/L, product).
T : Temperature (°C).
pH : Fermentation pH.

This multiplicative approach assumes independent effects. Models are validated against experimental data using statistical metrics like R² (>0.95 for good fits) and RMSE. Below, each factor’s detail is explained and provided with applicable equations, typical parameters for S. cerevisiae (from high-gravity ethanol studies), and modeling notes are provided.

Specific Growth Rate Calculator for Saccharomyces cerevisiae

Reference Strain: Novel Strain:

Substrate Model			Ethanol Model			Temp. Model			pH Model
	Ref. Strain	Novel		Ref. Strain	Novel		Ref. Strain	Novel		Ref. Strain	Novel
f(S):			g(P):			h(T):			i(pH):
μ_max			P_m			T_min			pH_opt
Kₛ			n or k (HO) or P_I			T_opt			σ
S_m or K_I,S			k (HIN)			T_max
n (L)						b or R
						c (factor)

Glucose (S, g/L, 0 - 300): 1

Ethanol (P, g/L, 0 - 120): 0

Temperature (T, °C, 10 - 45): 30

pH (3 - 6): 5.0

Instantaneous Specific Growth Rate (μ): Calculating...