Fig. 6

Influence of osmolality on growth and productivity of U. cynodontis ITA Max pH with limiting ammonium chloride concentration (1 g/L NH4Cl). (A) Course of the oxygen transfer rates. (B) Itaconic acid titer, OD and yield at the end of the respective fermentations. Osmolality was increased by addition of 0.1, 0.25 and 0.5 M NaCl. The reference medium has an osmolality of 350 mOsmol/kg. Cultivations were performed in 250 mL RAMOS flasks filled with 10 mL modified Verduyn medium with 25 g/L glucose at 30 °C, 350 rpm shaking frequency and a shaking diameter of 50 mm. 30 mM MES were added to the cultivations. The initial pH was set to 6.5 for all cultivations. The final pH reached 2.80 ± 0.01, 2.77 ± 0.01, 2.70 ± 0.01, and 2.65 ± 0.01 for the reference, 550, 850 and 1350 mOsmol/kg cultivations, respectively. Graphs show the mean of duplicates. Shadows and error bars show the minimum and maximum values. For clarity, only every second data point is shown