A HEURISTIC APPROACH TO FED-BATCH OPTIMIZATION OF STREPTOKINASE FERMENTATION

Previous studies have shown that the rate of formation of streptokinas e, a secondary metabolite, in batch fermentation is proportional to th e specific growth rate of the biomass, which in turn is inhibited by i ts substrate and the primary product (lactic acid). These kinetics sug gest the suitability of fed-batch operation to increase the yield of s treptokinase. A near-optimal feed policy has been calculated by the ch emotaxis algorithm, and it shows a substrate feed rate decreasing nonl inearly and vanishing after 11 hours. This is followed by batch fermen tation for a further 8 hours, at the end of which 12% more streptokina se is generated than by purely batch fermentation. Further improvement s in productivity are possible.