CHAPTER 10 BACTERIAL REPRODUCTION AND GROWTH OF MICROORGANISMS

For a growing bacterial culture, the generation time can be expressed as:

where g is the generation time, t is time, and n is the number of generations. The number of cells of a growing culture are expressed by the equation:

where N₀ is the number of cells at time 0, N, is the number of cells at any time (t) after time 0, and n is the number of generations. Rearranging this formula:

where g is the generation time, log N, is the logarithm to the base 10 of the number of bacteria at time t, log N₀ is the logarithm to the base 10 of the number of bacteria at the starting time, and t is the time period of growth.

By determining cell numbers during the period of active cell division, the generation time can be estimated. A bacterium such as Escherichia coli can have a generation time as short as 20 minutes under optimal conditions. Considering a bacterium with a 20-minute generation time, one cell would multiply to 1,000 cells in 3.3 hours and to 1,000,000 cells in 6.6 hours.

Date: 2015-02-28; view: 1039