An industrial scale reactor concept for continuous cultivation of immobilized animal cells (e.g. hybridoma cells) in a radial-flow fixed bed is presented, where low molecular weight metabolites are removed via dialysis membrane and high molecular products (e.g. monoclonal antibodies) are enriched. In a new “nutrient-split” feeding strategy concentrated medium is fed directly to the fixed bed unit, whereas a buffer solution is used as dialysis fluid. This feeding strategy was investigated in a laboratory scale reactor with hybridoma cells for production of monoclonal antibodies. A steady state monoclonal antibody concentration of 478 mg l-1 was reached, appr. 15 times more compared to the concentration reached in chemostat cultures with suspended cells. Glucose and glutamine were used up to 98%. The experiments were described successfully with a kinetic model for immobilized growing cells. Conclusions were drawn for scale-up and design of the large scale system.Abbreviations: cGlc – glucose concentration, mmol l-1; cGln – glutamine concentration, mmol l-1; cAmm – ammonia concentration, mmol l-1; cLac – lactate concentration, mmol l-1; cMAb – MAb concentration, mg l-1; D – dilution rate, d-1; Di – dilution rate in the inner chamber of the membrane dialysis reactor, d-1; D0 – dilution rate in the outer chamber of the membrane dialysis reactor, d-1; q*FB,Glc – volume specific glucose uptake rate related to the fixed bed volume, mmol lFB-1 h-1; q*FB,Gln – volume specific glutamine uptake rate related to the fixed bed volume, mmol lFB-1 h-1.
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