Fig. 4
Effect of different O2 concentrations on offline data of P. vulgatus shake flask cultivations. These data refer to the experiment shown in Fig. 3. Offline data of (a) HPLC analysis of produced organic acids including propionate, formate, succinate, acetate and lactate and remaining glucose from four biological replicates with standard deviation. (b) Carbon balance in % as function of the O2 concentration in the gas supply. The start of the fermentation was set to 100%. Initial samples were drawn after inoculation. (c) Final OD600nm and final pH from four biological replicates with standard deviation. Experimental setup is illustrated in Fig. 5b. Final OD600nm and final pH each differed statistically significant for the different oxygen concentrations, for final OD600nm: p < 0.001 and for final pH: p < 0.001. Medium: DMM-G, cGlucose = 6 g L− 1, cbuffer = 50 mM MOPS, T = 37 °C, n = 100 rpm, VL = 50 mL, initial OD600nm = 0.29, initial pH after inoculation = 6.9–7.1, vvm = 0.2 min− 1, different gas mixtures of O2 & 4% CO2 in N2, as indicated in the legend, N = 4