Fig. 2.

Relations between parameters used to describe bioreactor operational regimes for H₂/CO₂ and CO fermentations. a Dependency of non-dimensional electron donor uptake rate ($q_D^{\prime }$) and a non-dimensional mass transfer rate (${\text{mtr}}_D^{{}^{\prime }}=\frac{k_L{a}_D·\left(C_D^{\ast }-C_D\right)}{\text{max}\left[k_L{a}_D·\left(C_D^{\ast }-C_D\right)\right]}$) on dissolved electron donor concentration ($C_D$); b relation between ethanol volumetric productivity ($R_{\text{et}}$) and $q_D^{\prime }$; c estimated biomass concentration ($C_x$) as function of $q_D^{\prime }$. The figure includes curves with black dotted lines that represent the operation of CO fermentation when the effect of substrate inhibition in the kinetic model is minimized by maximizing the value of $K_I$