Fig. 3
Growth and γ-PGA production of B. licheniformis ATCC 9945 in standard mineral medium E. a Oxygen transfer rates (OTR) of six parallel flasks and optical density (OD600). b Derived online viscosity, measured offline viscosity, molecular weight, and concentration of γ-PGA. c Carbon source concentrations of glycerol, glutamic acid, and citric acid, and phosphate concentration. d Overflow metabolite concentrations of acetate, acetoin, and 2,3-butanediol. Initial values: pH = 7.4, 80 g L−1 glycerol, 20 g L−1 glutamic acid, 12 g L−1 citric acid. Cultivation conditions: T = 37 °C, 500 mL shake flasks, filling volume 100 mL, shaking frequency 250 rpm, shaking diameter 50 mm