FIG. 3.

Influence of Ca²⁺ (A), Mg²⁺ (B), or Sr²⁺ (C) on the growth of the C. glutamicum wild type with citrate as the sole carbon and energy source. Cells pregrown in CGXII minimal medium with 50 mM glucose, 50 mM citrate, and 20 mM CaCl₂, 50 mM MgCl₂, or 5 mM SrCl₂, respectively, were used to inoculate 50 ml of CGXII medium (containing 0.09 mM CaCl₂, 1 mM MgSO₄, and 0 mM SrCl₂) containing 50 mM citrate as the sole carbon and energy source. The cultures were incubated at 30°C on a rotary shaker at 120 rpm. The growth curves shown here are representative of those from three independent growth experiments with comparable results.