Fig. 4

Influence of polymer rings on the maximum oxygen transfer capacity (OTR_max) and the mixing time. 48 round well microtiter plate, transparent polymer rings without glucose crystals with d_inner = 8 mm (Fig. 2A), H_position = 0.0 mm, 1.5 mm, 3.5 and 5.5 mm, Z_height = 3 mm, 6 and 9 mm. As a control, wells without any polymer rings were evaluated, highlighted in the diagram with a purple dashed line ( - - - ). (A) Influence of polymer ring configurations on the OTR_max. Values were determined for cultivations with E. coli in Wilms-MOPS medium with 20 g/L glucose conducted in triplicates. Error bars depict the standard deviation, calculated for each set of triplicates. The oxygen transfer rate (OTR) was determined using the µRAMOS – device. Cultivation conditions: initial pH = 7.5, OD_{600 nm, start} = 0.5, V_L = 0.8 mL, T = 37 °C, n = 1000 rpm, d₀ = 3 mm. (B) Influence of polymer ring configurations on the mixing time. The mixing time was determined in triplicates with a colour change method, illustrated in Fig. 3. Error bars represent the standard deviation, calculated for each set of triplicates. Experimental conditions: V_L = 0.8 mL, T = 37 °C, n = 1000 rpm, d₀ = 3 mm.