Fig. 3

Effect of different MOPS concentrations on P. vulgatus shake flask cultivations in duplicates. Medium = DMMG, c_Glucose = 6 g L⁻¹, MOPS buffer (0, 50, 100, 150 mM), T = 37 °C, n = 100 rpm, V_L = 50 mL, initial OD = 0.3, initial pH after inoculation = 6.95–7.14, vvm = 0.2 min⁻¹, gas mix = 1% CO₂ and 99% N₂. a Online data of total gas transfer rate (TGTR) and b carbon dioxide transfer rate (CTR). Shadows indicate maximum and minimum values of duplicates (error bars). 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