Investigation of mathematical methods for efficient optimisation of aqueous two-phase extraction

Mathematical strategies were applied to optimise the extraction of recombin ant leucine dehydrogenase from E. coli homogenates and endoglucanase 1 from culture filtrates of Trichoderma reesei in polyethylene glycol-phosphate s ystems. The goal was to test mathematical tools which could facilitate the optimisation procedure in aqueous two-phase systems. A modified simplex app roach, the method of steepest ascent and a genetic algorithm were successfu lly applied and compared. The methods differ in the height of the optimum f ound, the number of experiments and the time required. The genetic algorith m proved to be an optimisation procedure which can be used well in aqueous two-phase systems. The simplex procedure has to be further improved. (C) 20 00 Elsevier Science B.V. All rights reserved.