Fig. 6.

Investigation of the influence of inoculation delay on CBP performance. a Shows the itaconic acid production for different CBP cultivations initially inoculated with T. reesei RUT-C30 (RFP1), that where inoculated with U. maydis after different time delays ranging from 0 to 5 days delay. b Shows the pH during cultivation. c Shows the protein concentration measured in the supernatant, which should mainly correspond to extracellular cellulase enzyme, d Shows the corresponding cellulase activity as measured by the filter paper assay. e shows the (NH₄)₂SO₄ concentration and f the KH₂PO₄-concentration during cultivation. g Shows the cellulose concentration during the cultivation as determined by the Updegraff assay and the increase in cellulose concentration after each feed. h Shows the corresponding dry weight of fungal biomass as estimated from the weight loss during Updegraff assay. The cultivation was performed starting from 30 g/L α-cellulose and 5 g/L glucose and was inoculated with 10⁶ spores/mL of T. reesei RUT-C30 (RFP1). The medium was buffered with 40 g/L CaCO₃. U. maydis pre-culture was added after the indicated intervals to an OD of 1.14. All cultures were fed with 60 g/L α-cellulose as indicated in g. The cultivation was performed with 25 mL medium in 250 mL Erlenmeyer flasks at 200 rpm, 50 mm shaking diameter and 30 °C. Values show single measurements sampled from the same flask. Error bars show standard deviation or deviation from the mean from technical replicates: a n = 1; b n = 1; c n = 3; d n = 4 to 6; e n = 3; f n = 2; g, h n = 1. Until the inoculation of U. maydis, the 3, 4 and 5 days delay experiments can be considered as biological replicates. Because the first data point of each experiment was sampled just before the inoculation of U. maydis, the traces of the 4 and 5 days delay experiment were connected with the first values of the 3 and 4 days delay experiment, respectively. The full dataset can be found in the Additional file 2: “Numerical data”