• KSBB Journal
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• 제15권6호
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• pp.556-559
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• 2000

Cyclodextrin Glucanotransferase(EC 2.4.1.19 : 1,4-${\alpha}$-glucano) transferase, cyclizing; CGTase) can be separated and recovered in an aqueous two-phase system composed of poly(ethylene glycol)(PEG)/dextran and PEG/salt. In an aqueous two-phase system consisting of PEG 35000 (5%) and dextran T2000 (7%), all cell and debris were collected at the interphase. CGTase partitioned to the denser dextran phase at an yield of 83.4%. On the other hand, in an aqueous two-phase system consisting of PEG 35000 (10%) and sodium phosphate (15%), CGTase partitioned to the denser salt phase at an yield of 95.5%. In order to recover CGTase using an aqueous two-phase system, the PEG/salt system proved to be more efficient than the PEG/dextran system in terms of yield and cost.

• 융복합기술연구소 논문집
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• 제4권2호
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• pp.23-26
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• 2014

As an effective separation method for biomolecules, aqueous two-phase systems based on ionic liquids were suggested. Hydrophobic ionic liquids are more expensive and viscous in spite of their usage in the ionic liquid/water biphasic extraction compared with hydrophilic ionic liquids. In case of aqueous two-phase systems using hydrophilic ionic liquids, they can be diluted in aqueous phase. Experimental results show that aqueous two phase systems can be formed by adding appropriate amount of ionic liquids to aqueous salts solutions. The viscosity of ionic liquid aqueous phase is proportional to the cation chain length in ionic liquids. It is founded that the ionic liquid based aqueous two phase systems are effective for the separation of biomolecules such as acrylic acid.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.761-768
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• 2019

Understanding the phenomena of formation of single drops is necessary to understand the hydrodynamics in solvent extraction equipment which are used for separation of nuclear materials. In this work, the phenomena of aqueous phase and organic phase drop formation at submerged nozzles are compared by conducting experiments with 30%TBP (v/v) in dodecane as the organic phase and nitric acid as the aqueous phase. Two different nozzles and three different nitric acid concentrations are used. For each nozzle and nitric acid concentration, velocity of the dispersed phase is varied. Drops of aqueous phase formed at downward oriented nozzles submerged in organic phase are observed to be smaller than the drops of organic phase formed at upward oriented nozzles submerged in aqueous phase. Correlations to estimate drop diameter are proposed.

• Journal of Microbiology and Biotechnology
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• 제6권5호
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• pp.352-357
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• 1996

The partition of proteins in the salt-rich phase of polyethylene glycol (pEG)/salt aqueous two-phase systems is limited by the salting-out effects of salt. The logarithm of the concentration of proteins partitioned in the salt-rich phase decreases linearly with increases in the concentration of salt in the salt-rich phase (salting-out). Therefore, the partition of a given protein in the salt-rich phase of aqueous two-phase systems can be estimated from the salting-out constant. The slope of the solubility line (salting-out con-stant) for a given protein is determined by the type of salt in the two-phase systems.

• 한국미생물·생명공학회지
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• 제22권5호
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• pp.531-537
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• 1994

This study was undertaken with objective of optimizing the conditions of fermentation in an aqueous two-phase system which is composed of polyethylene glycol (PEG) 20000 and crude dextran (Dx). The data were obtained and analyzed using the Box-Wilson's experimental design protocol and the response surface methodology. To reach this end a multilinear polynomial regres- sion model was developed, which can be utilized for the purpose of optimizing the extractive fermentation. Optimum conditions for batch fermentation with aqueous two phase system were found to be at 4.2~5.4% PEG/3.2~4.2% Dx range. The composition of the center was 4.8% PEG/ 3.6% Dx. Optimum operating conditions for initial sugar concentration and fermentation time were approximately 160 g/l, and 21~22 hr, respectively. Fermentation in the aqueous two phase system composed of 5% PEG/4% Dx showed increase of 23% in ethanol concentration, of 9.5% in ethanol yield, and of 19% in ethanol productivity as compared to the case of fermentation of neat Jerusalem artichoke juice.

• Food Science and Biotechnology
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• 제14권1호
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• pp.131-136
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• 2005

The selective extraction behavior of lactoferrin (Lf) from whey protein mixture was examined using reverse micelles formed by the cationic surfactant, cetyldimethylammonium bromide (CDAB). The major whey proteins, including ${\beta}$-lactoglobulin, ${\alpha}$-lactalbumin and bovine serum albumin, were solubilized from aqueous phase to organic phase while Lf was recovered in the aqueous phase. The solubilization behaviors of the proteins were manipulated by the process parameters such as the pH and salt concentration of the aqueous phase and the surfactant concentration in the organic phase. Efficient forward extraction was achieved with sodium borate buffer (50 mM, pH 9) containing 50 mM KCl and organic phase containing 100 mM CDAB. Based on SDS-PAGE and densitometry, about 96% of the initial Lf remained in the aqueous phase after forward extraction. The dialyzed Lf fully maintained its bacteriostatic activity against E. coli O157:H7.

• 한국미생물·생명공학회지
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• 제26권1호
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• pp.55-60
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• 1998

수용성 이상계에서 효율적인 추출발효를 수행하기 위해서는 생체촉매와 생성물이 서로 반대 상에 우세하게 분배되어아 한다. 일반적으로 분자량이 낮은 생성물은 양쪽상에 비슷하게 분배되므로, 상의 조성 등을 조절하여 한쪽상의 체적을 증가시켜 최대한으로 생성물을 추출하여야 한다. 본 연구에서는 PEI와 HEC으로 구성된 수용성 이상계에서 L. helveticus와 젖산의 분배에 미치는 다가 음이온의 농도, pH, 배지의 농도 및 생육배지 농도 등의 영향을 검토하였다. PEI의 상대 이온으로 작용하는 phosphate, sulfate 음이온수의 증가는 PEI 상의 체적을 감소시켜 하부상에 분배되는 세포의 양(Cb)을 감소시켰으며, sulfate 농도의 영향은 phosphate에 비해 적었다. 검토한 범위에서 대략 93%이상의 세포가 HEC-rich상부상에 분배되었다. 이상계에 생육배지 농도를 달리하여 첨가했을 때 배지 중에 존재하는 phosphate와 sulfate 농도에 따라 비슷한 경향을 나타냈지만 낮은 농도로 인하여 그 영향은 크지 않았다. Phosphate 농도에 따른 젖산분배를 검토한 결과 농도가 증가할수록 분배계수는 감소하였으며, 대략 85%가량의 젖산이 PEI의 하부상에 분배되었다. 이 결과로부터 수용성 이상계에서 전하를 띤 저 분자량의 생성물의 추출은 반대 전하를 띠는 폴리머를 하나의 상형성 풀리머로 사용함으로써 증진되었음을 알 수 있었다. 따라서 L. helveticus 세포는 95% 정도가 상부상에 분배되고 젖산은 85%정도가 하부상에 우세하게 분배되므로 PEI/HEC 이상계는 치즈유청으로 부터의 젖산의 추출발효에 가능성이 높은 시스템으로 응용될 수 있는 것으로 생각된다.

• 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.

• Journal of Microbiology and Biotechnology
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• 제9권5호
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• pp.589-592
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• 1999

Suspension cultures of Digitalis lanata were successfully performed in an aqueous two-phase system (ATPS) of 4.5％ polyethylene glycol (PEG) 20,000 and 2.8％ crude dextran. Cell growth in the medium containing an individual ATPS-forming polymer was inhibited due to the toxicity of PEG and a high viscosity of dextran. Formation of ATPS supported cell growth by showing a considerably decrease in viscosity and partitioning of cells into a PEG-lean dextran phase. It was found that an aqueous two-phase cultivation of plant cells in a stirred tank bioreactor could be successfully applied.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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• pp.135-140
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• 1992

The partitioning of recombinant human interleukin-2(rhII-2) in PEG 8000-dextran 38800 aqueous two-phase system has been investigated using three different sources of rhIL-2. In the case of pure rhIL-2, the solubility in a PEG-dextran two-phase system was low and most of rhIL-2 was partitioned into the bottom phase. For the recovery of rhIL-2 from insoluble protein aggregates, the inclusion bodies of recombinant E. coli were solubilized by the treatment with sodium dodecyl sulfate (SDS). The addition of SDS significantly enhanced not only the solubility of rhIL-2 but also the partitioning of rhIL-2 to the top phase. When the ratio of SDS to rhIL-2 was 2.0, the partition coefficient(K) and the recovery yield(Y) at the top phase were 4.5 and 88%, respectively, at pH 6.8. In order to reduce the recovery steps further, SDS was directly added to the intact recombinant E. coli cells and then partitioned into the PEG/dextran aqueous two-phase system. The observed partition coefficient ($K{\cong{3.0$) and recovery yield ($Y{\geq}80%$ )of this method were comparable to the rhIL-2 recovery from insoluble protein aggregates. The results obtained in this work indicate that PEG-dextran two-phase partitioning might provide a simple way for the recovery and partial purification of recombinant proteins which are produced as inclusion bodies.