Microbial Growth Website

IBERS: Institute of Biological, Environmental and Rural Sciences

Workings for Specific Growth Rate

Answer:  µ = 1.65 h^-1

The calculation is as follows:

The formula for the specific growth rate (µ) is:

µ = [log₁₀(N₂) - log₁₀(N₁)] x 2.303 / (t₂ - t₁)

t₁ and t₂ are the times (in hours) when the first and second samples were taken and measured. t₂-t₁ is thus the time between the two samples in hours and over which the observed increase in cell numbers occurred. Thus, for this experiment t₂-t₁ is 8 hours.  The calculation is thus:

µ = [log₁₀(5.5x10⁸) - log₁₀(1000)] x 2.303 / (8)

µ = 1.65 h^-1