Fig. 3

Effect of the filling volume on the growth of non-induced E. coli BL21 (DE3) pRhotHi YFP in synthetic Wilms-MOPS containing 20 g L⁻¹ glucose and 0.2 M MOPS buffer. All cultures were performed in parallel in one MTP. In groups of parallel cultures with different filling volumes the oxygen transfer rate (OTR, black lines) and the dissolved oxygen tension (DOT, blue lines) (a–d, m–p) are monitored. The number of parallel cultures is given in brackets behind the filling volume. Also scattered light at 650 nm (green lines) and YFP fluorescence (λ_ex = 480 nm; λ_em = 522 nm, orange lines) (i–l, u–x) are presented. The averaged maximum oxygen transfer capacity (OTR_max) is highlighted by a black horizontal dotted line for each filling volume. The volumetric oxygen transfer coefficient (k_La, red lines, Eq. 1) and the corresponding errors (light red shaded area, Eq. 2) were calculated (e–h, q–t) for OTR >5 mmol L⁻¹ h⁻¹ based on OTR and DOT. The end of oxygen limitation, which triggers the completion of YFP maturing, is indicated by a gray vertical dashed line for filling volumes of 1000 µL (d, h, l) and 1400 µL (p, t, x). Cultivation conditions: 0.1 g L⁻¹ infrared oxygen-sensitive nanoparticles; 48 round deep-well MTP without optodes, n = 1000 rpm, shaking diameter d₀ = 3 mm, 37 °C