Fig. 2

Impact of secondary substrate limitations on fermentations with pure sucrose. Influence of decreasing concentrations of nitrogen, phosphorus, and magnesium on A–C OTR and D–F malic acid production. A–C For clarity, only every fifth data point over time is represented as a symbol. Lines are drawn through all measuring points. Shadows indicate standard deviation of biological triplicates. D–E Samples were drawn after the sugar was fully consumed, as indicated by a drop in the OTR. Error bars indicate standard deviation of biological triplicates. Corresponding yields and space–time yields are provided in Additional file 1: Figure S5. Cultivation conditions: U. trichophora, µTOM device, 96 round deep well plates, modified Verduyn medium [25 g/L sucrose, 0.3 M MES (pH 7.2)], T = 30 °C, n = 1000 rpm, d₀ = 3 mm, V_L = 100 µL, OD_600,start = 0.1 [–]. A, D 0.5–6 g/L NH₄Cl, 0–6.6 g/L NaCl, 2 g/L KH₂PO₄, 0.4 g/L MgSO₄ B, E 6 g/L NH₄Cl, 0.06–2 g/L KH₂PO₄, 0–1.1 g/L KCl, 0.4 g/L MgSO₄ C, F 6 g/L NH₄Cl, 2 g/L KH₂PO₄, 0.025–0.4 g/L MgSO₄, 0–0.23 g/L Na₂SO₄