A bioreactor system and method for producing a biopol ymer

Abstract

Provided is a bioreactor system and a fermentation process employing continuous inline medium dilution in which concentrated medium and nutrients are blended with water or buffer and fed to the cell culture vessel of a bioreactor system, e.g. for production of antibodies and other recombinant proteins by mammalian cells.

1 . A bioreactor system for producing a product selected from a cell and a biopolymer expressed by a cell, wherein the bioreactor system is a continuous production system and wherein the bioreactor system comprises:
 a cell culture vessel ( 5 ) comprising a product harvest module ( 6 );   optionally, a bleed outlet ( 9 );   a medium container ( 1 ; 2 );   a water and/or buffer supply ( 3 ); and   an inline medium dilution system ( 4 ) for diluting concentrated medium from the medium container, the inline medium dilution system having an inlet and an outlet, wherein the inlet is in fluid communication with the medium container and the water/buffer supply, and wherein the outlet is in fluid communication with the culture vessel.   
     
     
         2 . The bioreactor system of  claim 1 , further comprising a sensor connected to the inline medium dilution system, wherein the sensor is located within or outside the cell culture vessel which sensor can measure the concentration or the amount of medium or the amount of selected components or nutrients in the cell culture vessel. 
     
     
         3 . The bioreactor system of any of  claim 1 , comprising an impurity filter unit ( 8 ). 
     
     
         4 . The bioreactor system of  claim 1 , wherein the inline medium dilution system contains conductivity and/or pH process analyzers. 
     
     
         5 . The bioreactor system of  claim 1 , wherein the medium container has a volume of at least 50 L, such as at least 100 L, e.g. at least 250 L. 
     
     
         6 . The bioreactor system of  claim 1 , comprising at least two medium containers, each medium container being in fluid communication with an inlet of the inline medium dilution system. 
     
     
         7 . A method for producing a biopolymer using a bioreactor system according to  claim 1 , the method comprising:
 (a) fermenting cells expressing the biopolymer in a suitable medium under suitable conditions to allow expression of the biopolymer by the cells,   (b) harvesting the biopolymer by removing medium comprising biopolymer and impurities via the product harvest module, and   (c) isolating the biopolymer from the harvested medium;   wherein, during fermentation, the method further comprises:   adding concentrated medium from a medium container and water or buffer from the water/buffer supply to an inlet of the inline medium dilution system to result in diluted medium, and feeding the diluted medium containing nutrients to the culture vessel through an outlet to replenish nutrients consumed by the cells and to compensate for medium removed for harvesting of the biopolymer.   
     
     
         8 . The method of  claim 7 , wherein concentrated medium in the medium container is diluted at least by a factor of at least two with water or buffer before being fed to the culture vessel, e.g. by a factor of at least three, four or five. 
     
     
         9 . The method according to  claim 7 , wherein concentrated medium from at least two medium containers is mixed with water or buffer prior to being fed to the culture vessel. 
     
     
         10 . The method of  claim 7 , wherein the cell density in the cell culture vessel during the fermentation reaches at least 10 million cells per ml medium, e.g. at least 20 million cells per ml medium, such as at least 30 million cells per ml medium, such as at least 40 million cells per ml medium. 
     
     
         11 . The method according to  claim 7 , wherein concentrated medium is mixed with water/buffer and the concentrated medium in the medium container(s) is kept at a reduced temperature of below room temperature, e.g. 1-10° C., such as about 5° C., wherein the concentrated medium has been pre-heated, or wherein the diluted medium is pre-heated from a reduced temperature of below room temperature, e.g. 1-10° C., such as about 5° C. prior to being added to the culture vessel. 
     
     
         12 . The method according to  claim 7 , wherein the cells are mammalian cells, e.g. selected from the group consisting of CHO (Chinese hamster ovary) cells, hybridomas, BHK (baby hamster kidney) cells, myeloma cells, HEK-293 cells, PER.C6® cells, human lymphoblastoid cells and NSO cells. 
     
     
         13 . The method according to  claim 7 , wherein the biopolymer is a polypeptide or protein, e.g. an antibody or antibody fragment, a blood clotting factor, a cytokine, an enzyme or a peptide hormone; or a virus particle or part thereof.