(Air, ■), 3.32 ± 0.12 % (●), 8.86 ± 0.24 % (Δ), and13.84 ± 0.27 % ( )

Figure 5: Influence of different levels of inlet CO2 on δ-aminolaevulinic acid and specific pyruvate carboxylase activity in 5L parallel fermentaters. Symbols: the inlet CO2 concentrations were controlled at 0.03%.