Response surface optimization of the separation of DL-tryptophan using an emulsion liquid membrane

Response surface methodology was applied to optimize the separation Of DL-t ryptophan from aqueous solution. DL-tryptophan was extracted into an emulsi on liquid membrane containing Aliquat-336 in oleyl alcohol. The carrier con centration (10-30%, by volume). pH (10-14) and initial amino acid concentra tions (1-7 mM) were the critical components of the separation optimized. Ex periments were performed at 150 rpm stirring rate, for 30 min extraction ti me with equal volumes of organic and aqueous phases. The response surface e quation to predict the extraction yield in the above range of critical comp onents is Y = 100.72 + 31.83x(1) + 0.15x(2) + 3.38x(3) - 21.41x(2)(1) - 5.39x(2)(2) - 7.11x(3)(2) + 1.19x(1)x(2) - 3.26x(1)x(3) - 2.30x(2)x(3) where Y is the response. (extraction yield), Maximum Y (100%) was obtained by employing the following predicted optimum extraction conditions: a pH of 12.46, a carrier concentration of 22.22%, and an initial amino acid concen tration of 4.97 mM. (C) 2001 Elsevier Science Ltd. All rights reserved.