Fig. 5

Effect of changing the initial pH-value on P. vulgatus shake flask cultivations in duplicates. Medium = DMMG, c_Glucose = 6 g L⁻¹, c_buffer = 50 mM MOPS, T = 37 °C, n = 100 rpm, V_L = 50 mL, initial OD = 0.3, different initial pH, vvm = 0.2 min.⁻¹, gas mix = 1% CO₂ and 99% N₂, tested initial pH values after inoculation: 6.98, 7.07, 7.22, 7.29, 7.33, 7.45, 7.61, 7.73, 7.80, and 7.93. a Online data of total gas transfer rate (TGTR) and b carbon dioxide transfer rate (CTR). Symbols in brackets indicate different experiments. c Offline data of produced organic acids including propionate, formate, succinate, acetate, and lactate and remaining glucose, d initial osmolality, final OD_600nm, and final pH as mean values of biological duplicates. Samples to measure initial osmolality were drawn immediately after inoculation. Samples to measure final OD_600nm, final pH, and HPLC analysis were drawn immediately after termination of the experiment, indicated by the last online data point in a and b. e Molar carbon balance in % of the initial carbon, calculated with Eqs. 3-5. Initial values include acids from preculture. The corresponding maximum and minimum of duplicates (error bars) can be found in Supplementary Fig. S3