Fig. 1.

Viable cell density (a) and cell viability (b) over process time for all batch fermentations. (Black symbols represent processes at pH 7.0, blue symbols at pH 6.8, red symbols at pH 7.2; closed symbols represent processes at pCO₂ 5 %, half-closed at 12.5 % and open symbols at 20 %; triangles represent processes at pO₂ 25 %, squares at 10 %, circles at 40 %). High pH values led to high viable cell densities but concurrently to shorter process time due to faster depletion of the main c-source. Cell viabilities stayed at high values as long as glutamine was available