상 접촉법을 이용하여 BSA를 음이온 계면활성제인 AOT와 isooctane으로 구성된 역미셀상으로 정추출한 뒤, 과잉수용액상과 접촉시켜 역추출하는 실험을 행하였다. 본 연구에서는 pH와 염의 종류 및 농도가 추출 효율에 미치는 영향에 주목하였다. 0.1 M의 KCl, NaCl, MgCl2 그리고 CaCl2과 같은 1:1 염 혹은 1:2 염을 수용액에 첨가하면 첨가한 염의 종류에 따라 pH=5-7 사이에서 최대의 정추출 효율을 보였다. CaCl2와 NaCl의 경우, 1 M까지는 염의 농도가 증가함에 따라 정추출 효율도 증가하였으나 MgCl2의 경우에는 특이한 경향을 보였다. 염의 농도가 낮거나 pH가 낮은 경우에는 단백질이 광범위하게 수용액상과 유기상간의 계면에 침전되는 것은 주목할 부분이다. 역미셀의 water-pool 크기는 물에 대한 계면활성제의 몰비인 WO를 측정하여 추산하였다. MgCl2의 경우에는 pH변화에 관계없이 WO=20의 거의 일정한 값을 보인 반면 CaCl2와 KCl의 경우 염 농도가 증가함에 따라 WO는 감소하였다. 역추출의 경우에는 등전점 이상의 높은 pH와 높은 염농도에서 최고의 역추출 효율을 보였다.

By using the phase-transfer method, bovine serum albumin(BSA) was solubilized into a reverse micellar phase consisting of sodium bis(2-ethylhexyl) sulfosuccinate(AOT) and isooctane. In order to recover the solubilized protein, the laden organic phase was brought into contact with an excess aqueous phase under a prescribed condition. Of particular interest in this study were the effects of pH and the added salt type and concentration on the forward and backward extraction efficiency. When salt containing univalent or divalent cations such as KCl, NaCl, MgCl2, or CaCl2 were added to the aqueous phase at a concentration of 0.1 M, maximum forward extraction efficiency was achieved at a pH ranging from 5 to 7, depending on the added salt type. Increasing the salt concentration up to 1 M led to an enhanced forward extraction efficiency for CaCl2 and NaCl, while the addition of MgCl2 beyond 0.1 M showed an anomalous trend. Further, it was noteworthy that to a large extent the protein precipitated in the interface between the organic and aqueous phases at lower pHs and lower salt concentrations. The size of the reverse micelle water pool was estimated by measuring the molar ratio of the surfactant to the water, W0. Independently of pH in the aqueous phase, the resulting value of W0 was almost constant, eg., 20 for MgCl2. However, the value of W0 decreased with increase of the salt concentration in the cases of KCl and CaCl2. It was also shown that the backward extraction efficiency of the protein increased with pH and salt concentration in the excess aqueous phase. The higher the salt concentration in the excess aqueous phase, the smaller the value of W0 in the organic phase.

Solubilization Reverse Micelle AOT BSA Extraction

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