Yeast Growth Kinetics

Two simple models that allow for basic understanding of yeast or microbial growth kinetics are exponential growth model and logistic growth model. The exponential growth model can be use as the educational foundation but can only rarely be applied in real world, in difference the logistic growth model can be used to model real world data sets as it represents population growth kinetics for yeast or microbial population that starts to grow exponentially but slows down as resources become scarce and carrying capacity is reached or growth is influence by other environmental constraints. Fundamentally, therefore at high yeast concentrations, factors like nutrient depletion, waste accumulation, and space limitations slow down growth, preventing unchecked exponential expansion.

Basic Yeast Growth Kinetics Models:

• Exponential Growth Model -  yeast or microbial cell population  grow unrestricted, meaning they keep multiplying without any limitations. Data plotting generates the J-curve.

Mathematical Formula: X_F= X_ie^µt

• Logistic Growth Model - yeast or microbial cells population starts growing exponentially but slows down as resources become scarce, eventually reaching a maximum carrying capacity (K). The data plotting generates the S-curve.

Mathematical Formula: X_F= (K* X_i) / X_i+(K-X_i) e^-µt

Where:

• X_F = Final cell concentration at final time
• X_i = Initial cell concentration
• µ = Specific Growth Rate
• K = Carrying capacity
• t = Time

As it accounts for resource limitations the logistic growth model is a more realistic model for yeast and microbial populations. It is widely used in biotechnology, ecology, and fermentation industries to optimize growth conditions and predict culture behavior. Basic version of the Yeast Growth Calculator shown on the left can be used to model some basic data. In addition, FermAxiom LCC developed advanced yeast growth kinetics calculators that are available to our registered users and industrial partners.