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Fig. 3 | BMC Biotechnology

Fig. 3

From: Black glucose-releasing silicon elastomer rings for fed-batch operation allow measurement of the oxygen transfer rate from the top and optical signals from the bottom for each well of a microtiter plate

Fig. 3

Schematic experimental setup for mixing time determination and exemplary evolution of a mixing time experiment. (A) A GoPro Hero 4 camera is mounted onto a shaker table facing a clear microtiter plate (MTP) on a light module. A pipette filled with sulphuric acid is fixed with a clamp above the microtiter plate, which is equipped with polymer rings. The wells of the microtiter plate were filled with a 3 vol-% bromothymol blue solution. By adding 0.2 M sulphuric acid, a colour change from blue to yellow can be observed. (B) The frames taken from a video show the characteristic colour change. For evaluation with the self-written MATLAB®-tool, two areas are depicted. The starting point of mixing time (tmixing) determination is defined by the time point the acid drop passes the maximum liquid height (shown by red circle). The yellow square depicts the area for evaluation of the colour change. Experimental conditions: T = 37 °C, n = 1000 rpm, d0 = 3 mm, VL = 0.8 mL, transparent polymer ring, Hposition = 0 mm, Zheight = 3 mm

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BMC Biotechnology

ISSN: 1472-6750

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