EFFECTS OF CULTURE CONDITIONS ON PRODUCTI ON OF TPA IN A MICRO-FILTRATION HOLLOW-FIBER BIOREACTOR

The effects of culture conditions on the production of tissue plasmino gen activator (tPA) were studied with recombinant baby hamster kidney (BHK) cells in a micro-filtration hollow fiber bioreactor using Dulbec co's Modified Eagle medium with serum. The disserved oxygen concentrat ion (DO) and pH of the medium had a strong influence on tPA productivi ty, and it was optimal for tPA production to control the pH at 7.2 and the DO at an air saturated concentration. When tPA was harvested from the extra-capillary space (EC), the production was 1.25-fold that whe n it was harvested from the intra-capillary space (IC). tPA production was maintained at an almost constant level throughout the culture, ev en though the serum concentration was reduced from 5 to 0.2%. When the culture conditions were set at pH 7.2, DO 6.5 mg/l, serum concentrati on 0.2%, and EC harvesting, the mean tPA production was 335 mg/d, or 1 72 mg/d/m(2) of the hollow fiber membrane. Stable continuous cultivati on was achieved for 78 d, and 20 g of tPA was produced in total after the serum concentration was reduced to 0.2%.