Calculation of the bacterial growth rate from a spectrophotomer growth curve?

Question

Typically the microbial growth in liquid cultures is monitored by turbidity. Data is obtained with a spectrophotometer to measure optical density at 600nm. The slope of the bacterial kinetic curve in exponential phase is the growth rate. But I have seen two ways of calculate the growth rate: 1. Growth rate = Maximum slope value of the Kinetic curve 2. $Log_{10}$ transformation of the growth data and then calculate the slope. I think the second one is right if you want to calculate the generation time: generation time = $\\frac{ln(2)}{Growth rate}$. What is the correct way to calculate the growth rate and then generation time?

Answer 1

You are correct. To obtain a positive line, you would take the log of the growth data along the y axis.