• Bulletin of the Korean Chemical Society
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• 제22권8호
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• pp.897-902
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• 2001

The protein back-extraction processes were discussed from the viewpoint of the micelle-micelle interaction. Bovine serum albumin (BSA) suppressing the cluster formation of reverse micelle (positive value of ${\beta}pr)$ has the high back-extra cted fraction (Eb), but cytochrome c enhancing the formation of reverse micelle (negative value of ${\beta}pr)$ has the low back-extracted fraction, relatively. We have also examined quantitatively the effects of alcohol addition and protein solubilization on the percolation process of reverse micelle. The alcohols suppressing the formation of micellar cluster (high values of ${\beta}t)$, remarkably improved the back-extraction rates of BSA and cytochrome c. The values of ${\beta}t$, defined by the variation of percolation process, and the back-extraction behavior of proteins have a good linear correlation. These results indicate that the micelle-micelle interaction or micellar clustering plays an important role in the back-extraction process of proteins.

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.873-877
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• 2004

The relationship between the behaviors of c.c.lipase back-extraction and their percolation phenomena by using AOT reverse micellar systems (RVMS) has been studied by the addition of a small amount of additives to organic phase such as thiols and nonionic-surfactants focusing on micelle-micelle interactions. The values of ${\beta}_t$ defined by the variation of percolation processes and back-extraction behaviors of c.c.lipase have a good linear correlation. The hydrophobicity of additive molecules suppressing the cluster formation of reverse micelles (high values of ${\beta}_t$) improved the back-extraction behavior of c.c.lipase. The back-extraction fraction and its rate of c.c.clipase are increased with decreasing of the value of hydrophilic lipophilic balance (HLB) and increasing of the hydrophobicity per additive molecules added to reverse micellar systems (RVSM) in the same additives concentration.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 춘계공동학술발표회요약집
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• pp.316.1-316
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• 2002

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.828-832
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• 2014

The spectroscopic properties of quercetin (QCT) were studied in the AOT reverse micelle by fluorescence spectroscopy. Because the molecular structure of QCT is completely planar, excited state intramolecular proton transfer (ESIPT) occurs between the -OH at C(5) and carbonyl oxygen via intramolecular hydrogen bonding. This ESIPT happens at the $S_1$ state but not at the $S_2$ state. Because QCT is a good donor-acceptor-conjugated molecule at the excited state, this molecule can emit strong fluorescence but shows no $S_1{\rightarrow}S_o$ emission due to this ESIPT. Since the $S_2{\rightarrow}S_1$ internal conversion was very slow due to the small Franck-Condon factors, $S_2{\rightarrow}S_o$ fluorescence emission was observed. All of the experimental results indicated that the QCT resided at the bound water interface and that the position of solute did not change significantly in the micelle at various water concentrations.

• Journal of Microbiology and Biotechnology
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• 제8권5호
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• pp.466-470
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• 1998

The basic and optimum conditions for the extraction of peroxidase from Chinese cabbage root applying the reverse micelle system were investigated. In order to purify Peroxidase (POX) from crude extract of Chinese cabbage roots, isooctane containing 110 mM Aerosol OT (AOT) was well mixed with the same volume of crude extracts containing 50 mM NaCl and 30 mM Tris-HCI buffer of pH 8.0. After centrifugation, AOT reverse micelle containing the isooctane phase were mixed with 80 mM Tris-HCI buffer at pH 7.0 containing 1 M KCl. From these operations, POX was purified 20-fold with a 60% yield. For further purification, DEAE-Toyopearl column chromatography was applied, and it showed a single protein band on SDS-polyacrylamide gel electrophoresis. The resulting POX showed 93-fold purification with a 40% yield.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.157-160
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• 2000

본 연구에서는 $20^{\circ}C$에서 음이온 계면활성제인 AOT와 isooctane으로부터 형성된 reverse micelle을 이용하여 수용액상에 녹아있는 BSA인 모델 단백질을 분리하는 실험을 행하였다. 염의 농도가 0.1M에서 최고 가용화 효율은 KCl, NaCl, $MgCl_2$ 그리고 $CaCl_2$의 경우 각각 pH=5, 5.5, 7, 5 근처임을 알 수 있었다. 또한 매우 낮은 염 농도에서는 가용화는 일어나지 못하고 계면이 혼탁한 현상을 보였다. 특히 $CaCl_2$의 경우에 염 농도에 대하여 최고의 가용화 효율을 보였다.

• 한국환경과학회지
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• 제11권9호
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• pp.987-992
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• 2002

Nanosized titania sol has been produced by the controlled hydrolysis of titanium tetraisopropoxide(TTIP) in sodium bis(2-ethylhexyl)sulfosuccinate(AOT) reverse micelles. The physical properties, such as crystallite size and crystallinity according to R ratio have been investigated by FT-IR, XRD and UV-DRS. In addition, the photocatalytic degradation of bromate has been studied by using batch reactor in the presence of UV light in order to compare the photocatalytic activity of prepared nanosized titania. It is shown that the anatase structure appears in the 300~$600^{\circ}C$ calcination temperature range and the formation of anatase into rutile starts above $700^{\circ}C$. The crystallite size increases with increasing R ratio. In the photocatalytic degradation of bromate, the photocatalytic decomposition of bromate shows the decomposition rate increases with decreasing initial concentration of bromate and with increasing intensity of light.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.981-987
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• 2011

The anomalous spectroscopic properties of quercetin-3-O-rhamnoside (QCRM) and quercetin-3-O-rutinoside (QCRT) in AOT reverse micelle were studied. The excited state intramolecular proton transfer (ESIPT) occurs through the strong hydrogen bond between the -OH at position 5 and the carbonyl oxygen. Because the ESIPT can only happens in the $S_1$ state and the Franck-Condon factor involved in the $S_2\;{\rightarrow}\;S_1$ internal conversion is small, the $S_2\;{\rightarrow}\;S_o$ emission alone appears. Because the molecular planarity is improved at the interior of the micelle, the excited state intramolecular charge transfer in the $S_1$ state is extended, and the excited state is more tolerable for any quenching effects in the micelle. Therefore, an $S_1\;{\rightarrow}\;S_o$ emission was newly discovered under this micelle microenvironment. For the $S_2\;{\rightarrow}\;S_o$ emission, the quantum yields increase but the quantum yield of the $S_1\;{\rightarrow}\;S_o$ emission approximately decreases as the water concentration in the micelle increases.

• Journal of Microbiology and Biotechnology
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• 제24권12호
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• pp.1690-1698
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• 2014

Partial purification of glucoamylase from solid-state fermentation culture was, firstly, investigated by reverse micellar extraction (RME). To avoid back extraction problems, the glucoamylase was kept in the original aqueous phase, while the other undesired proteins/enzymes were moved to the reverse micellar organic phase. The individual and interaction effects of main factors (i.e., pH and NaCl concentration in the aqueous phase, and concentration of sodium bis-2-ethyl-hexyl-sulfosuccinate (AOT) in the organic phase) were studied using response surface methodology. The optimum conditions for the maximum recovery of the enzyme were pH 2.75, 100 mM NaCl, and 200 mM AOT. Furthermore, the optimum organic to aqueous volume ratio ($V_{org}/V_{aq}$) and appropriate number of sequential extraction stages were 2 and 3, respectively. Finally, 60% of the undesired enzymes including proteases and xylanases were removed from the aqueous phase, while 140% of glucoamylase activity was recovered in the aqueous phase and the purification factor of glucoamylase was found to be 3.0-fold.

• 한국식품과학회지
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• 제21권4호
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• pp.542-548
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• 1989

AOT-Isooctane 역마이셀계를 이용한 단백질 추출 및 회수에 영향을 미치는 여러 가지 요인과 단백질 혼합물로부터의 선택적인 분리에 대해 연구 검토하였다. Lysozyme, ${\alpha}-chymotrypsin$은 AOT 100 mM까지 높은 추출율을 보이다가 100 mM 이상에서는 점차 감소하였고, BSA는 200 mM까지 추출율이 증가하다가 그 이상에서는 감소하였다. pH에 따른 단백질의 역마이셀로의 추출은 등전점이 높은 lysozyme이 pH4-10, ${\alpha}-chymotrypsin$과 trypsin은 각각 pH5, 5.4에서 95% 이상의 높은 추출율을 보였으며 등전점이 낮은 pepsin과 BSA는 어떤 pH 영역에서도 거의 추출되지 않았다. 이온강도를 증가시켰을 때 단백질의 추출이 감소하였고, Wo가 감소하면서 역마이셀의 크기도 감소하였으며 이온에 따라 $Mg^{2+}>Na^+>Ca^{2+}>K^+$의 순으로 타났다. 단백질 회수시에는 전반적으로 추출과는 반대경향을 보였으며, lysozyme의 경우 회수하는 수용액이 1.0M KCl-pH 12.2일 때, ${\alpha}-chymotrypsin$은 0.5M KCl-pH6.7, trypsin은 0.5M KCl-pH 12.6일 때 85% 이상의 높은 회수율을 얻었다. BSA/lysozyme 혼합물로부터 각각의 분리를 시도하였는데, BSA는 forward transfer 후 역마이셀내로 추출되지 않은 채 수용액상에 남게하고 lysozyme은 역마이셀내로 추출시킨 후 backward transfer 과정을 거쳐 새로운 수용액상으로 회수하여 전기영동으로 확인하였다.