Immobilization of the slime mould Dictyostelium discoideum for the continuous production of recombinant human antithrombin III.

Recombinant vegetative Dictyostelium discoideum cells were immobilized inside a porous matrix by an inorganic membrane that was permeable to nutrients but not to cells, in order to produce recombinant human antithrombin III. Cells so entrapped could reach up to 15 times higher biomass densities compared with organisms growing freely in suspension. The high cell concentration maintained in the immobilized cell bioreactor caused an increase in specific and volumetric productivity. In continuous operation a maximum volumetric antithrombin productivity of 56 ng h-1 ml-1 catalyst bulk volume was attained at a dilution rate of 0.016 h-1. In addition, the good retention of metabolic activity for several weeks as well as the convenient form of storage and regeneration of the catalytic system were shown.