Fig. 7

Influence of itaconic acid concentrations on U. cynodontis ITA Max pH with limiting ammonium chloride concentration (1 g/L NH4Cl). (A) Course of the oxygen transfer rates with increasing itaconic acid concentrations added at the beginning of the experiments. (B) Produced itaconic acid titer (in addition to the amount added at the beginning), OD and yield after 95 h. 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 1.88 ± 0.04, 4.42 ± 0.04, 5.08 ± 0.03, and 5.39 ± 0.01 for the reference, 20, 40 and 80 g/L added itaconic acid cultivations, respectively. (A) Graphs show the smoothed mean (Savatzky-Golay) of duplicates. Shadows show the minimum and maximum values of the unsmoothed data. (B) Error bars show the minimum and maximum value of duplicates. For clarity, only every fourth data point is shown