Embodiments of the invention relate to a bioreactor system and to a method for regulating parameters of at least two bioreactor bags provided on one and the same rocking part of the bioreactor system.
A commonly used type of bioreactor for cultivating cells is provided on a rocker unit. Mixing of the culture is accomplished by the wave-induced agitation which is performed by the rocker unit. The conditions in the cell culture can be regulated by different means, for example the temperature can be regulated by providing heat, pH can be regulated by adding acid or base and the amount of liquid/media can be controlled.
Usually one bioreactor bag is provided on the rocker unit and one or more load cells are provided somewhere on the rocker unit in order to measure the weight of the content of the bioreactor bag. The regulation of for example temperature, pH and amount of liquid as described above can then be adapted for different weights. If the weight of the cell culture is changed during the cultivation time (for example by the addition of for example media or acid or base) it is suitable to adapt further regulation/control activities to these new weight conditions. For example more heat is required to increase temperature for a larger volume of cell culture and more base is needed in order to increase pH for a larger volume of cell culture.
A method previously used for being able to individually control two bioreactors provided on the same rocker unit was to assume that the initial weight relationship between the two bags would be maintained throughout the process.
A problem with this previously used method is that if the two bioreactors are controlled individually the content of the two bioreactors will also change individually and the initial weight relationship between the two bags will not be maintained. If a wrong weight is assumed the control method will not be optimal.