Fig. 3

Growth of U. cynodontis ITA Max pH on different carbon sources available in complex substrates without nitrogen limitation. The basic medium contained 5 g/L fructose, glucose and lactate each, denoted as “Reference”. The concentration of fructose, glucose and lactate was each increased to 10 g/L. The curves in the figure are denoted by the type of additional carbon source. (A) Course of the oxygen transfer rates. (B) Consumed oxygen (integral of the data in (A)). Dashed vertical lines show the depletion of the fructose and glucose. The first dashed line shows the depletion of fructose and glucose for the reference and the cultivation with increased lactate, while the second dashed line shows the depletion for the cultivations with increased sugars. Cultivations were performed in 250 mL RAMOS flasks filled with 10 mL modified Verduyn medium 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 6.37 ± 0.02, 6.22 ± 0.01, 6.23 ± 0.02, and 7.56 ± 0.03 for the reference, increased fructose, glucose and lactate cultivations, respectively. Errors describe the deviation of the maximum and minimum pH value from the mean of duplicates. Graphs show the mean of duplicates. Shadows show the minimum and maximum values. Due to high reproducibility of the measurements, the standard deviation might not be visible for every data point. For clarity, only every second data point is shown