Discontinuous fed batch processing with the use of alternating bioreactors

1. A method for the production of a proteinaceous biological substance by culturing mammalian cells that produce said biological substance in a bioreactor, said method comprising:

a) providing a bioreactor with a cell culture comprising said mammalian cells suspended in a culture medium; and

b) performing at least one culture and harvest cycle comprising incubating said cell culture in said bioreactor until the cell culture has reached the exponential phase or the early stationary phase; and when said exponential phase or the early stationary phase is reached, harvesting the culture medium with the proteinaceous biological substance in a harvest system that functions by separating the cells from the culture medium containing the biological substance by flowing the cell culture into a centrifuge that maintains the cells as a concentrated fluidized bed through the continuous balanced action of centrifugal and fluid flow forces, whereby the fluid flow force is applied by the inflow of fresh medium whereby the cells and culture medium are separated; and

(c) feeding essentially all cells back into a different bioreactor for continued culture together with fresh culture medium.

2. A method according to claim 1 , comprising at least 2 culture and harvest cycles.

3. A method according to claim 1 , wherein during incubation of the cell culture at least part of the cell culture is continuously flowed into a separation system that comprises a size selective semipermeable membrane,

wherein the membrane separates the cells and the proteinaceous biological substance from substances having a lower molecular weight than the proteinaceous biological substance,

thereby creating a cell- and biological substance-free effluent that is outputted and a cell- and biological substance-containing fluid stream that is fed back into the bioreactor, and

wherein loss of said effluent is at least compensated by feeding culture medium or a component thereof into the bioreactor.

4. A method according to claim 2 , wherein the cell culture incubations in culture and harvest cycles subsequent to said at least one culture and harvest cycle are performed in different or alternating bioreactors.

5. A method according to claim 1 , wherein said cells are CHO cells.

6. A method according to claim 1 , wherein said proteinaceous biological substance is an antibody or antigen binding fragment thereof.

7. A method according to claim 1 , wherein said cells are cultured in a fed-batch culture system.

8. A method according to claim 1 , wherein the volume of the cell culture exceeds the capacity of the harvest system.