The shaking table of an orbital shaker moves in a circle. The diameter of this circle is called the “shaking diameter”.
Most commonly used diameters are
On all Kuhner shakers the orbital movement can be changed at any time.
No. Microtiter plates can also be shaken with a larger diameter; the smaller the diameter, the faster the speed required (e.g. 700 rpm with 3mm). When choosing a larger diameter such as 50mm, a speed of 250 rpm may be enough to guarantee proper mixing and oxygen transfer.
In a shaken bioreactor the mechanical stress on the cells is usually considerably less than in a stirred system. In a stirred bioreactor there are two stress effects: on the one hand you have small eddies near the impeller blades and on the other hand, small bubbles burst on the liquid surface because the vessel is sparged from the bottom. In a shaken bioreactor there is surface aeration and the shaking movement gives uniform mixing without any local power inputs.
The smaller the volume and the longer the fermentation time, the more the evaporation rate affects your cultivation. Evaporation can be reduced by using special lids, stoppers, adhesive foils etc. One example is the Duetz system for microtiter plates. It is also necessary to humidify the incubator chamber.