Fig. 4
Effect of different osmolalities on P. vulgatus shake flask cultivations in duplicates. Medium = DMMG, cGlucose = 6 g L−1, cbuffer = 50 mM MOPS, T = 37 °C, n = 100 rpm, VL = 50 mL, initial OD = 0.21, initial pH after inoculation = 7.03–7.08, vvm = 0.2 min−1, gas mix = 1% CO2, and 99% N2, 220 mOsmol kg−1 as reference osmolality, osmolalities of 301, 349, and 396 mOsmol kg−1 adjusted by addition of NaCl. Online data of a total gas transfer rate (TGTR) and b carbon dioxide transfer rate (CTR), shadows indicate maximum and minimum values of duplicates (error bars). Offline data of c produced organic acids including propionate, succinate, acetate and lactate, and remaining glucose; d initial osmolality, final OD600nm, and final pH as mean values of biological duplicates. Samples to measure initial osmolality were drawn immediately after inoculation. Samples to measure final OD600nm, 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