• Korean Chemical Engineering Research
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• 제51권5호
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• pp.575-579
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• 2013

최근 바이오 플라스틱인 Polytrimethylene terephthalate (PTT)의 원료물질인 1,3-프로판디올의 생물학적 생산이 주목받고 있다. 발효를 통한 1,3-프로판디올의 생산에 있어 부산물로 생성되는 젖산, 숙신산을 포함한 카르복실산들은 1,3-프로판디올의 경제적인 생산을 어렵게 한다. 본 연구에서는 카르복실산 부산물이 포함된 1,3-프로판디올 수용액으로부터 1,3-프로판디올의 효율적 분리정제를 위해 수용성 알콜과 염으로 구성된 수상이성분계를 이용한 추출을 적용하였다. 알콜과 염으로 구성된 수상이성분계 형성은 하부상에 존재하는 염의 염출효과에 의한 것이며 이로 인해 1,3-프로판디올이 상부상으로 이동된다. 추출효율을 알콜의 사슬길이가 짧을수록, 염의 세기가 높을수록 높아졌으며 최대 98%의 회수율을 얻을 수 있었다. 또한 발효 시에 부산물로 형성되는 카르복실산은 1,3-프로판디올과 동반추출 되지 않았으며 1,3-프로판디올의 추출효율에도 영향이 없는 것으로 나타났다. 그러므로 본 연구에서 적용된 친수성 알콜과 염으로 구성된 수상이성분계는 카르복실산 부산물로부터 1,3-프로판디올을 선택적으로 분리하는데 효과적임을 알 수 있다.

• 대한화학회지
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• 제57권6호
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• pp.684-690
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• 2013

Since a glycerol molecule has three active sites, two ${\alpha}$ and one ${\beta}$ hydroxyl groups; it undergoes condensation by releasing water molecules to produce linear, nonlinear and heterocyclic oligomers. The Gibbs free energy (G), enthalpy (H) and internal energy (E) of 7 diglycerol, 15 triglycerol and 23 tetraglycerol isomers were calculated at B3LYP level of theory using 6-311++G(d, p) basis set, in both gas and aqueous phases. Linear oligomers, ${\alpha}{\alpha}$-diglycerol, ${\alpha}{\alpha}$, ${\alpha}{\alpha}$-triglycerol and ${\alpha}{\alpha}$, ${\alpha}{\alpha}$, ${\alpha}{\alpha}$-tetraglycerol, were found to be the most stable oligomers in aqueous phase. It was found that the stability of cyclic oligomers decreases as the size of their rings increases. Cyclic oligomers are produced by dehydration of the acyclic ones which is an endothermic reaction while its ${\Delta}G$ is negative. The dehydration reaction is less endothermic in aqueous phase.

• 한국미생물·생명공학회지
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• 제20권2호
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• pp.190-195
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• 1992

Polythylene glycol/dextran 수성 2단계에서 polyethylene glycol의분자량과 농도가 증가할수록 체적비는 증가하고 분배계수는 감소하였다. 또한 dextran의 분자량이 증가할 수록 체적비는 감소하고 분배계수는 증가하였다. 한편 dextran의 농도가 증가할수록 체적비와 분배계수는 감소하였다.

• Korean Chemical Engineering Research
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• 제52권5호
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• pp.627-631
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• 2014

본 연구에서는 아크릴산 추출을 위한 효과적인 분리공정으로서 모폴린계 이온성 액체/$K_2HPO_4$에 의한 수상이성분계를 적용하여 수상이성분계 형성 특성 및 아크릴산 추출 효율에 대한 모폴린계 이온성 액체의 양이온 알킬사슬 길이의 영향을 고찰하였다. 실험 결과 $K_2HPO_4$ 수용액에 적정량의 모폴린계 이온성 액체를 첨가함에 따라 안정한 수상이성분계가 형성됨을 확인할 수 있었으며 이성분계 형성능력은 [HMMor][Br]>[OMMor][Br]>[BMMor][Br]> [EMMor][Br]의 순서로 나타났다. $K_2HPO_4$ 수용액을 기준으로 모폴린계 이온성 액체의 수상이성분계 형성 능력은 기존의 이미다졸계와 큰 차이가 없었으며 친수성알콜/$K_2HPO_4$와 비교했을 경우에는 적은양으로도 수상이성분계 형성이 가능하였다. 모폴린계 이온성 액체를 이용한 수상이성분계 추출에 있어 아크릴산 추출 효율은 50~90%의 범위를 가지며 이 값들은 이미다졸계와 큰 차이가 없었다. 모폴린계 이온성 액체가 이미다졸계 이온성 액체에 비해 경제적으로 생산할 수 있으므로 모폴린계 이온성 액체와 $K_2HPO_4$로 구성된 수상이성분계는 아크릴산을 포함한 각종 생물공정에 의한 제품 분리에 효과적임을 알 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.244-249
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• 2007

Fluidic conditions for the separation of phases were surveyed in a microfluidic aqueous two-phase extraction system. The infusion ratio between polyethylene glycol (PEG) and dextran solution defines the concentrations of each polymer in micro-channel, which determine the phase-separation. The appropriate ratio between PEG (M.W. 8000, 10%, w/v) and dextran T500 (M.W. 500000, 5%, w/v) in order to perform the separation of phases of both polymers was observed as changing the mixed ratio of both polymers. Based on the fluidic conditions, stable two-phase solutions were obtained within 4% to 8% and 3% to 1% of PEG and dextran, respectively. In addition, the characteristics of the two-phase were discussed. The separation technique studied in the paper can be applied for the implementation of a lab-on-a chip which can detect various biological entities such cells, bacterium, and virus in an integrated manner using built in a biosensor inside the chip.

• KSBB Journal
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• 제8권2호
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• pp.178-184
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• 1993

Extractive fermentations with the extract of Jerusalem artichoke in an aqueous-two-phase-system of polyethyleneglycol(PEG) and dextran(Dx) were investigated to obtain the effects of composition of PEG and Dx on both fermentation ,characteristics and partition ratio of alcohol. The specific growth rate of K. Fraglis CBS 1555 increased with a decrease of concentration of PEG and Dx. It augmented along with concentration of initial sugar up to 80g/l but decreased thereafter. The specific production rate of alcohol showed a rising tendency up to 100g/lof initial sugar, whereafter represented a decreasing trend. The partition ratio of alcohol between two phases augmented according to decrease of Dx comic. and increase of PEG cone. regardless of initial sugar concentrations. The ratio, however, decreased with Increment of initial sugar concentration at constant composition of PEG and Dx. The partition coefficient of alcohol had an ascending effect to the increase of PEG cone, but it had little effect on the changes of concentrations of Dx and initial sugar. The present study suggests that the optimum composition of PEG and Dx in the aqueous-two-phase-system by extractive fermentation were around 6.5%(w/v) of PEG and 3%(w/v) of Dx in considerations of emulsion state, sedimentation and separation of two phases, alcohol partition ratio, and specific growth rate.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.515-518
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• 1997

Resident time of the centrifugal extractor for organic phase extraction using a height controlled separator weir and a divert plate is the important factor that affects significantly the chemical material extraction and the productivity in the chemical and mechanical processes. In this paper, it describes the design of the device for extraction of an organic phase from radioactive wastes, and considers phase separating weir and divert disk, both being designed to be adjustable in their positions, for effectively separating an organic phase. A height-adjustable separating weir unit used for separating the organic phase from the aqueous phase using a phase separating weir and designed to control the height of the separating weir as desired so as to allow the weir to be positioned at a boundary layer between two separated phases. The centrifugal extractor controls satisfactorily the mixed reaction time of two phases within the separator regardless of the variations of the mixing ratio of the two phases and the rotating speed of the extractor, is designed to be adjustable in its position in the vertical direction, thus allowing the user to appropriately select the mixed reaction time of the two phases within the extractor as desired. From development of a centrifugal extractor, it can effectively recover such usable elements, and preferably reducing the output quantity of radioactive wastes.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.145-148
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• 2000

Large-scale resolution of epoxides by the yeast Rhodotorula glutinis was demonstrated in an aqueous/organic two-phase cascade membrane bioreactor. Due to the chemical instability and low solubility of epoxides in aqueous phases, an organic solvent was introduced into the reaction mixture in order to enhance resolution of epoxide. A cascade hollow-fiber membrane bioreactor was used (i) to minimize the toxicity of organic solvents towards the epoxide hydrolase of Rhodotorula glutinis, and (ii) to remove inhibitory amounts of formed diol from the yeast cell containing aqueous phase. Dodecane was selected as a suitable solvent and 1,2-epoxyhexane as a model substrate. By use of this membrane bioreactor, highly concentrated (0.9 M in dodecane) enantiopure (>98% ee) (S)-1,2-epoxyhexane (6.5 g, 30% yield) was obtained from its racemic mixture.

• 한국환경과학회지
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• 제9권2호
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• pp.159-164
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• 2000

For the purpose of development of a liquid membrane permeator which separates metal ions from aqueous solutions continuously and effectively, a continuous membrane permeator with the membrane solution trapped between extraction and stripping phases by two micro-porous hydrophilic films was manufactured. Experimental researches on the separation of zinc ion from aqueous solutions were performed in the liquid membrane permeator with 30 vol % D2EHPA solution in kerosine as liquid membrane. As results, the liquid membrane permeator separates zinc ion from aqueous solutions continuously and effectively in the wide range of operating conditions. A simple mass transfer rate model using equilibrium constant of the extraction reaction for the system used were proposed, and the model was compared with experimental results of separation of zinc ion in the permeator. And the effects of operating factors, such as space time, pH of extraction solution, extraction temperature, on the separation rate of zinc ion in the permeator were experimentally examined.

• 대한화장품학회지
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• 제12권1호
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• pp.34-61
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• 1986

The microstructural transitions of aqueous micellar solutions of cetyltrime-thylammonium bromide and sodiumdodecyl sulfate by adding 1-hexanol were investigated, measuring the concentrations of equilibrated phases and the electrical conductivities at the low concentrations of surfactants, where the solobilities of 1-hexanol varied significantly, at 3$0^{\circ}C$ and 45$^{\circ}C$. Ternary phase diagrams of multiphase regions, constructed by liquid chromatography analysis and by counting the number of phase of samples, consisted of one three-phase region and three two-phase regions. One of the two-phase regions was found to equilibrate an aqueous micellar solution and a liquid crystal, and had a critical point between them. Near this region, the solubility curve varied abruptly, and the isotropic solution turned birefrigent. The conductivities of the single phase regions above the critical point increased up to a certain point as 1-hexanol added, and then decreased, representing the microstructural transition at the supercritical region. Further, the solubility of 1-hexanol in aqueous micellar solution was found to increase as temperature and the number of hydrophilelipophile balance of surfactants increase.