Figure 4.

Fermentation profile of C. saccharolyticus (a) grown in a chemostat under high H₂ partial pressure at two different glucose concentrations (see Section 4.4), (b) grown in a chemostat without NH₄⁺ in the medium under low and high H₂ partial pressure (see Section 6.4). The switch from 20 mM to 40 mM glucose containing-medium and the switch from low to high H₂ partial pressure cultivation condition is indicated by a vertical line. Acetate (open triangles), lactate (open squares), ethanol (crosses), CO₂ (open circles), oxaloacetate (asterisks), glucose out (open diamonds) and CDW (plus sign). Chemostat cultivation parameters (3 L reactor, 1 L working volume, pH = 7.0 (NaOH), temp 70 °C, D = 0.1 h⁻¹, low P_H2 [sparging (4 L/h) with N₂ gas and stirring speed = 250 rpm]), high P_H2 [headspace flushing (4 L/h) with H₂ gas and stirring speed = 50 rpm]).