Doubling time

Definition

Doubling time is the period required for a population of microorganisms to double in number. It is a critical parameter in understanding microbial growth dynamics.

5 Must Know Facts For Your Next Test

1. Doubling time can be influenced by environmental factors such as temperature, pH, and nutrient availability.
2. The formula to calculate doubling time is Td = (ln 2) / µ, where µ is the specific growth rate.
3. Shorter doubling times indicate faster microbial growth rates.
4. In batch cultures, doubling time can change over different phases of growth: lag, log (exponential), stationary, and death phases.
5. Doubling time is often used in microbiological studies to compare the growth rates of different microbial species or strains.

Review Questions

• What environmental factors can influence the doubling time of a microorganism?
• How do you calculate the doubling time using the specific growth rate?
• Why might the doubling time vary in different phases of a batch culture?

Related terms

Specific Growth Rate: The rate at which a microorganism grows per unit time under specific conditions.

Lag Phase:

The initial phase in microbial growth where cells are adapting to new conditions and not dividing.

Exponential Phase:

The phase in microbial growth where cells divide at a constant rate, leading to exponential increase in population size.