Figure 1.

Differences in total citrate yields and production rates on glucose as carbon source. Aspergillus niger strains NW186 and NW305 were either grown without addition of iron (circles), or varying amounts of Fe(II)SO₄ (triangles = 1 g·L⁻¹, squares = 10 g·L⁻¹) and supplemented with either arginine (filled symbols) or excess citrulline (empty symbols). Sample points for RNA extraction (t = 48 h) are marked in orange. Measurement points were taken once every 24 h and show the average of two biological replicates. Note that glucose consumption, rather than time, is plotted on the x-axis.