Özlem AYDOĞAN, Emine BAYRAKTAR, Ülkü MEHMETOĞLU

Ters Misel Sistemi ile L-Aspartik Asit Ekstraksiyonu

Bu çalışmanın amacı, hidrofilik bir amino asit olan L-aspartik asitin ekstraksiyonunu ters misel sistemiyle incelemektir. Son yıllarda, amino asitlerin fermentasyonla üretimi giderek önem kazanmaktadır. Bu amino asitler, sulu çözeltilerinde seyreltik olarak bulunurlar ve üretim ortamlarında fazla bulunan substrat, inorganik tuzlar ve yan ürünlerden ayrılması gerekmektedir. Günümüzde ters misel ekstraksiyonu ile amino asitlerin, üretim ortamından ayrılması üzerine çalışmalar yoğunlaşmıştır. Bu çalışmada, ters misel fazı; yüzey aktif madde olarak, aliquat-336, eş yüzey aktif madde olarak, 1-dekanol ve apolar çözücü olarak izooktan içermektedir. Deneyler 150 rpm karıştırma hızında, 30 oC'da, 60 dakika süre ile eşit hacimde ters misel ve sulu fazlar ile gerçekleştirilmiştir. L-aspartik asit derişimi sıvı kromatografi (HPLC) ile analizlenmiştir. Ekstraksiyon verimi, pH ve aliquat-336 derişiminin artmasıyla ve başlangıç amino asit derişiminin azalmasıyla artmıştır. Maksimum ekstraksiyon verimi (% 68) pH 12'de, yüzey aktif madde derişimi 200 mM'da ve başlangıç amino asit derişimi 5 mM'da elde edilmiştir.

Anahtar Kelimeler:

L-aspartik asit, Amino asit, Ters misel, Ekstraksiyon, Aliquat-336.

Extraction of L-Aspartic Acid with Reverse Micelle System

The aim of this study is to investigate the extraction L-aspartic acid which is a hydrophobic amino acid with reverse micelle system. Production of amino acids by fermentation has been more important in recent years. These amino acids are obtained in dilute aqueous solutions and have to be separated from excess substrate, inorganic salts and by-products. Recently, separation of amino acids from fermentation media by reverse micelle extraction has received a great deal of attention. In this study, reverse micelle phase includes aliquat-336 as a surfactant, 1-decanol as a co-surfactant and isooctane as an apolar solvent. Experiments were performed at 150 rpm stirring rate, at 30 oC, for 30 min extraction time with equal volumes of reverse micelle and aqueous phases. Concentration of L-aspartic acid was analyzed by liquid chromatography (HPLC). The extraction yield increased with increasing pH and aliquat-336 concentration and with decreasing initial amino acid concentration. Maximum ekstraction yield (68 %) was obtained at pH of 12, surfactant concentration of 200 mM and an initial amino acid concentration of 5 mM.

Keywords:

L-aspartic acid, Amino acid, Reverse micelle, Extraction, Aliquat-336.,

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