I don't know of any specific software that estimates growth rates, however I am sure something may exist. The method I would use would be to grow the bacteria of interest in the substrate of interest and take samples at regular intervals. I would then plate these samples to get my CFU/mL at the different time points. I would convert these values into log10 and plot in Excel, I would expect to see something that is close to a straight line (I would also have Excel provide me the best fit line equation). The equation for doubling rate is DR = Log10(2/slope). This will give you the doubling rate in decimal form. You can convert it into minutes by multiplying that value by 60. I hope this helps, let me know if you have any questions.