FIG. 3.
Effect of changing the initial glycerol concentration in the culture on the glycerol concentration at the point of entry into stationary phase (○). Stationary-phase entry was the point at which the OD600 stabilized (Fig. 2A). Complete experiments were done at least three times for each initial glycerol concentration except for the experiment with 21.3 mM glycerol, which was done only once. At least two glycerol determinations were done for each data point, and values shown are means ± SE. It was experimentally determined that 15.7 mM glycerol was used during exponential growth of the culture, with an initial glycerol concentration of 16.4 mM. For cultures where the amount of glycerol was not limiting (≥16.4 mM), the concentration of glycerol that was expected to be left in the medium upon entry into stationary phase was calculated by subtracting 15.7 from the initial concentration (□).