Kinetic study of growth throughout the lag phase and the exponential phase of Escherichia coli

An equation describing bacterial growth throughout lag and exponential phases was derived based on the assumption that parent cells inoculated into a fresh medium initiate cell growth according to the first order reaction kinetics (the FOR model) and that all cells once cell growth is initiated continue cell growth at a constant rate. The length of a lag time was given by three parameters: the retardation time, t_r, the rate of growth initiation of parent cells, λ, and the specific growth rate, μ. Escherichia coli inoculated into a fresh medium was shown to grow in accordance with theoretical prediction. When non-growing cells taken from different-aged cultures were used as inocula, changes in the length of the lag time depended solely on the λ value.