AMINE-BASED AQUEOUS POLYMERS OF THE SIMULTANEOUS TITRATION AND EXTRACTION OF LACTIC-ACID IN AQUEOUS 2-PHASE SYSTEMS

The partitioning of 10% (w/w) lactic acid in ethylene oxide propylene oxide (EOPO) random copolymers and dextran T500 aqueous two-phase syst ems was studied. An analysis of variance design was applied to investi gate the effect of pH, polymer concentration, and addition of polyethy leneimine to the aqueous two-phase systems. The lowest lactate partiti on coefficient of 0.09 was obtained at pH 6 in the systems containing 7.2% (w/w) polyethyleneimine. The use of polyethyleneimine as titratin g base during the fermentative production of lactic acid was evaluated in batch fermentations with 100 g/l glucose. Yield and productivity o f polyethyleneimine titrated fermentations compared with those obtaine d in fermentations titrated with NaOH and KOH. (C) 1998 Elsevier Scien ce B.V. All rights reserved.