Fig. 1

Variation of the steady-state concentrations of a biomass, b ethanol, c dissolved oxygen and residual glucose with respect to the feed concentration of glucose at fixed k_la ≈ 50 h⁻¹ and four dilution rates, namely, 0.07 h⁻¹ (yellow), 0.10 h⁻¹ (blue), 0.15 h⁻¹ (green), and 0.20 h⁻¹ (violet). The arrows point in the direction of increasing D. The lines in the carbon- and oxygen-limited regimes are best fits to Eqs. (14)–(16) and (23)–(25), respectively. The lines in the dual-limited regime are obtained by linearly interpolating the end points of the carbon- and oxygen-limited regimes. The inset in c shows the dissolved oxygen levels