REUSE OF SPENT CELL-CULTURE MEDIUM IN PILOT-SCALE AND RAPID PREPARATIVE PURIFICATION WITH MEMBRANE CHROMATOGRAPHY

Based on experiments in bench scale, a recycling of spent cell culture medium was performed in a 100-1 pilot scale bioreactor. The cell cult ivation has been done as a repeated batch procedure after the initial batch in the following four repeated batches spent medium from the pre vious batch was partially re-used. After microfiltration and ultrafilt ration a part of the filtrate was mixed with a concentrate of amino ac ids and glucose, sterile filtered and subsequently filled back into th e bioreactor. Up to 65% of the harvested cell- and product-free spent medium was re-used in each repeated batch. This procedure results in a saving of pure and waste water volume and saving of supplemented prot eins as transferrin, insulin and Lipoproteins and, therefore, also in a reduction of the production costs. A strongly acidic membrane ion ex changer was evaluated for the ability to purify the monoclonal antibod ies from the pilot scale cultivation. Within minutes, gram quantities of product could be purified in a high flux system, especially develop ed for this purpose, achieving purities of 80%. The capacity of the ac idic membrane ion exchanger was found in former investigations to be 1 mg cm(-2) with recoveries up to 96%. Final purification was carried o ut by gel column filtration.