The specific growth rate (μ) describes how quickly biomass increases relative to the current biomass concentration, typically measured in h⁻¹.
The doubling time (td) is the time required for the biomass concentration to double. It is inversely related to the specific growth rate by the formula:
td = ln(2) / μ
Where:
- td: Doubling time (hours).
- ln(2): The natural logarithm of 2 (approximately 0.693).
- μ: Specific growth rate (h⁻¹).
The doubling time is equivalent to the generation time for unicellular organisms, representing the length of a cell cycle.