Fig. 6

Growth Kinetics of E. faecalis Wild-Type and Mutant Strains in Response to pH and Osmotic Stress Growth rate of the double mutant strains Kup⁺ (light-blue triangle), KimA⁺ (orange square), and JH2-2 (light-green circle) at different initial pH values, 5.7, 7.0 and 8.0, respectively (a, b and c). Growth curves were performed in a semi-defined medium deficient in K⁺ (MSSM supplemented with amino acids, vitamins, and CAA 0.1%) and the addition of different concentrations of KCl (0.2, 0.5, 10, and 100 mM) was evaluated. For each condition, μ_max was calculated and plotted as a function of the KCl concentration added to the medium. The wild-type E. faecalis JH2-2 strain was used as a control. Growth curves of the double mutant strains Kup⁺, KimA⁺, and JH2-2 were performed in the MSSM medium at initial pH values of 5.7, 7.0, and 8.0, (d, e and f, respectively). The arrow in a, b and c graph indicates the condition under which 1% NaCl was added to perform the growth curves in D, E, and F.