Fig. 3

Physiological parameters for A. niger B36 and three overexpression strains during chemostat cultivation at a dilution rate of 0.1 h⁻¹. a CO₂ evolution rate (CER) in mmol/L/h; b Formation of the by-product oxalic acid in µmol/g cell dry weight; c Dry cell weight in gDCW/kg; d Yield of total secreted protein per gram biomass; e glaA relative gene expression level at the exponential growth phase and during steady state; f Relative gene expression level of the overexpressed genes during exponential growth and steady state; g Intracellular NADPH level at steady state. Data represent the mean ± SD from two independent cultures which were measured in technical triplicates. Significance values were calculated with the two-tailed t-test with independent variables (*p < 0.05, **p < 0.01, ***p < 0.001). Straight lines in a-d indicate the switch from batch to chemostat cultivation. OE gsdA: strain overexpressing gene gsdA; OE gndA: strain overexpressing gene gndA; OE maeA: strain overexpressing gene maeA