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For 24-square deepwell microtiter plates, culture volumes between 2.5 ml and 3.5 ml are generally used**, either at 300 rpm on a shaker with a 25 mm amplitude (photo and video on the left) or at 225 rpm on a shaker with a 50 mm amplitude (photo and video on the right). Under both conditions oxygen transfer rates for 2.5 ml cultures are approximately 35-39 mmol O2 l-1 h-1  (corresponding to k La values of 180-200 h-1). ** preferably use a culture volume of 2.5 ml, especially when the sandwich cover has to be take off occasionally (e.g. for sampling or feeding)
25 mm shaker amplitude 300 rpm
50 mm shaker amplitude 225 rpm
Hydrodynamics inside wells of a 24-square deepwell microplate
The mixing times under the above conditions are less than a second, as determined by adding a drop of acid to an alkaline solution (containing a pH indicator), and following the colour change with a high-speed camera.
50 mm shaker amplitude 225 rpm
To obtain higher oxygen-transfer rates (50 mmol O2 l-1 h-1 or higher), shaking at 50 mm/300 rpm is possible. Preferably do not use higher cultures volume than 2.5 ml per well (2 ml may be even better) to prevent the culture fluid to touch upon the sandwich cover (and so possbly cause cross contamination when the cover is taken off)
50 mm shaker amplitude 300 rpm
E. coli cultures (2.5, 3, and 3.5 ml) growing on a mineral medium, 15 times slowed down
Mixing time test during orbital shaking at an amplitude of 50 mm, 225 rpm, 15 times slowed down
Still from high-speed MP4 video below
Still from high-speed MP4 video at the right
39*  mmol O2 l-1 h-1
35*  mmol O2 l-1 h-1
* Duetz et al. (2004) Biochemical Engineering Journal 17: 181-185 (data determined enzymatically using glucose oxidase, horse radish peroxidase, and ABTS)
Still from high-speed MP4 video below
Still from high-speed MP4 video at the right