• Bioindustry News
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• v.13 no.2
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• pp.13-17
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• 2000

새로운 분리공정으로써 크로마토그래피를 이용하고자 하는 노력들이 활발하게 진행되어지고 있는 가운데, 기존의 전통적인 크로마토그래피를 더욱 발전시킨 시도들이 행하여지고 있다. 여기에 부합하여 약 20여년 전부터 연구되기 시작한 Displacement ion-exchange chromatography는 현재 활발한 연구가 진행되어지고 있으며, 전형적인 preparative chromatography에 비해 많은 장점을 가지고 있다. Displcement ionexchange chromatography는 displacer를 사용하여, 고농도의 원료 물질을 효율적으로 단시간내에 처리할 수 있는 공정으로 기존의 preparative chromatography의 문제점이었던 꼬리끌기 현상과 희시현상을 대폭 감소시킬 수 있게 되었다. 따라서, displacement ion-exchange chromatography 공정에서의 가장 큰 과제인 비선형 등온선 영역에서의 거동과 분리공정 조작선의 결정 및 고성능의 displacer에 대한 연구가 요구되어지고 있으며, 본 총론에서는 이온교환 크로마토그래피 공정에서 displacement ion exchange chromatography를 이용한 단백질의 분리에 대하여 고찰하고자 한다.

• Journal of Oral Medicine and Pain
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• v.25 no.1
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• pp.9-28
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• 2000

The purpose of this article, the first part of series, is to describe the general theory applicable to various chromatographic procedures. History of chromatography, separation of matters, classification of chromatography, underlying principles of separation in chromatography, covering resolution, column efficiency, column selectivity, and capacity factor, movement of solute in chromatographic phase, including elution development, displacement development, and frontal analysis, were discussed. Mathematical description of plate theory and thermodynamic viewpoint of retention were emphasized.

• Biotechnology and Bioprocess Engineering:BBE
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• v.2 no.2
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• pp.117-121
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• 1997

Glutamic acid can be crystallized inside cation exchange column when displacer NaOH concentration is high enough to concentrate displaced glutamic acid beyond its solubility limit. Resulting crystal layer of glutamic acid was moved with liquid phase through the column, and thus could be eluted from the column and recovered in fraction collector. For the purpose of enhancing crystal recovery, effects of operating parameters on the crystal formation were investigated. The increase in the degree of crosslinking of resin favored crystal recovery because of its low degree of swelling. Higher concentration of displacer NaOH was advantageous. If NaOH concentration is too high, however, crystal recovery was lowered due to the solubility-enhancing effects of high pH and ionic strength. The decrease of mobile phase flow rate enhanced crystal recovery because enough time to attain local equilibrium could be provided, but film diffusion would control the overall crystal formation with extremely low flow rate. Lower temperature reduced solubility of glutamic acid and thus favored crystal formation unless the rate of ion exchange was severely reduced. The ion exchange operated by displacement mode coupled with crystallization was advantageous in reducing the burden of further purification steps and in preventing purity-loss resulted from overlapping between adjacent bands.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.660-666
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• 1994

The effects of temperature and flow rate of eluent on the separation of adjacent lighter lanthanide pairs (La : Ce, Ce : Pr, Pr: Nd) have been studied with displacement chromatography. Two serial columns packed with Amberlite 120 cation exchange resin are used for loading and separation. The retaining ion is $H^+$ ion and the eluent is 0.012M and 0.015M of EDTA solution. The columns and the eluent are maintained at the temperature of 90$^{\circ}C$ and pressurized to reduce vaporizing in the ion-exchange resin column. The eluated solution is analyzed directly with ICP-AES. The separation factors of the lanthanide pairs, La: Ce, Ce :Pr, and Pr: Nd, are 4.6, 2.8, and 1.9, respectively and are higher than that from theoretical calculation at 25$^{\circ}C$. When the flow rate is reduced from 2.5 ml/min to 1.5 ml/min, the HETP is reduced from 1.60 cm to 0.88 cm. The separation efficency can be improved at lower flow rate of eluent and higher operating temperature. The recoveries of pure lanthanides than 99.9% are 49∼77% from this separation.

• Advances in environmental research
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• v.9 no.3
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• pp.215-232
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• 2020

Crude oils are essential source of energy. It is majorly found in geographical locations beneath the earth's surface and crude oil is the main factor for the economic developments in the world. Natural crude oil contains unrefined petroleum composed of hydrocarbons of various molecular weights and it contains other organic materials like aromatic compounds, sulphur compounds, and many other organic compounds. These hydrocarbons are rapidly getting degraded by biosurfactant producing microorganisms. The present study deals with the isolation, purification, and characterization of biosurfactant producing microorganism from oil-contaminated soil. The ability of the microorganism producing biosurfactant was investigated by well diffusion method, drop collapse test, emulsification test, oil displacement activity, and blue agar plate method. The isolate obtained from the oil contaminated soil was identified as Bacillus subtilis. The identification was done by microscopic examinations and further characterization was done by Biochemical tests and 16SrRNA gene sequencing. Purification of the biosurfactant was performed by simple liquid-liquid extraction, and characterization of extracted biosurfactants was done using Fourier transform infrared spectroscopy (FTIR). The degradation of crude oil upon treatment with the partially purified biosurfactant was analyzed by FTIR spectroscopy and Gas-chromatography mass spectroscopy (GC-MS).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.55-59
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• 2000

A specific and sensitive sandwich enzyme-immunoassay (EIA) using Avidin-Biotin complex was developed for the measurement of GTH II levels in pituitary content and pituitary cell culture medium of the rainbow trout-(Oncorhpchus mykiss). Biotin-salmon GTH II rabbit IgG (sefondary antibody) wai purified by a protein A sepharose affinity chromatography column and that was biotinylated by using Biotin-N-hydroxysuccinimide ofter (BNHS). Non-biotin salmon GTH II rabbit IgG (first antibody) was obtained only through a protein A sepharose affinity chromatography column. The assay was performed by the so-called 'sandwich' method using a microtiter plate, A dose-response curve was obtained between $0.12 to 125 ng/ml$ of salmon GTH II. The displacement curves for pituitary extraction and pituitary cell culture medium of testosterone-treated rainbow trout were Parallel to the standard curie. The intra-assay and inter-assay coefficients of variation (CV) were $8.2{\%} (N=5) and 12.5{\%} (N=6)$, respectively, This assay system was used to measure the amount of GTH II that accumulated in the culture medium of dispersed pituitary cells in testosterone-treated immature rainbow trout, The accumulation was increased with the amount or salmon gonadotropin-releasing hormone. GTH II values determined by the present method were well correlated with those determined by radioimmunoassay. As a result, this assay system was found to be suitable for the measurement of GTH II for pituitary extraction and pituitary culture medium in many salmonid fishes.

• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1229-1243
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• 2013

In this paper, an air isolate (NITT6L) has been screened based on hemolytic activity, emulsification activity, drop collapsing test, and oil displacement test, as well as lipase activity. It was found that strain NITT6L was able to reduce the surface tension of the medium from 61.5 to 39.83 mN/m and could form stable emulsions with tested vegetable oils. Morphological, biochemical, 16S rRNA sequencing analyses, and fatty acid methyl ester analysis using gas chromatography confirmed that the air isolate under study was Pseudomonas aeruginosa. Characterization of the biosurfactant using agar double diffusion assay revealed that the biosurfactant was anionic in nature, and CTAB-methylene blue assay and Molisch test revealed its glycolipid nature. The FT-IR spectrum confirmed that the crude biosurfactant was a rhamnolipid. Using unoptimized medium containing sucrose as the carbon source, the isolate was found to produce 0.3 mg/ml of rhamnolipid in batch cultivation (shake flask) at $37^{\circ}C$ and pH 7. Optimization of the medium components was carried out using design of experiments and the yield of rhamnolipid has been enhanced to 4.6 mg/ml in 72 h of fermentation.

• KSBB Journal
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• v.11 no.5
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• pp.606-612
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• 1996

A specific ammino auid in a mixture can be crystallized inside an ion exchange column when displacer concentration is high enough to concentrate the amino acid in a pure band beyond its solubility limit. Glutamic acid formpd a discrete crystal layer in a cation exchanger column by operating displacement development mode and using a high concentration of displacer NaOH. The glutamic acid crystal formed was eluded from the column with the effluent stream and collected in a fraction collector. When 1.0 M of NaOH was used as a displacer, more than 60% of the loaded glutamic acid was recovered as crystal. The continuous crystallization and dissolution of crystal occurred, resulting in apparent movement of the crystal along the column without clogging or pressure increase. NaOH was proved a better displacer than NaCl because hydroxide ions neutralized hydrogen ions released from the resin and thus reduced the number of hydrogen ion competing with sodium ion for re-adsorption. The displacement development process coupled with crystallization provided higher concentration and recovery of glutamic acrid than conventional chromatography.

• Polymer(Korea)
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• v.34 no.6
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• pp.547-552
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• 2010

Biodegradable polymers have gained enormous attentions in the pharmaceutical and biomedical applications, especially in drug delivery. In this work, we report the synthesis and characteristics of high molecular weight polyoxalate with ~75000 Da. Hydrolytic degradation kinetics and degradation products were characterized by nuclear magnetic resonance and gel permeation chromatography. Polyoxalate is a semicrystalline and thermally stable polymer with a glass transition temperature of ${\sim}35^{\circ}C$, which is suitable for drug delivery applications. The hydrophobic nature of polyoxalate allows it to be formulated into nanoparticles and encapsulate drugs using a conventional oil-in-water emulsion/solvent displacement method. Polyoxalate nanoparticles also exhibited excellent cytotoxicity profiles. It can be suggested that polyoxalate has great potential for numerous biomedical and pharmaceutical applications.

• Journal of Pharmaceutical Investigation
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• v.28 no.2
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• pp.121-126
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• 1998

The solubility and physicochemical stability of caroverine hydrochloride (CRV), an antispasmodic, in buffered aqueous solutions were studied using a reverse phase high performance liquid chromatography. The solubilty of the drug at pH 2.76-5.40 was similar at the range 31.9-36.2 mg/ml $(34^{circ}C)$, but, at the pH higher than 6.0, markedly decreased. The use of polyethylene glycol 400 as a cosolvent did not increase the solubility at any compositions examined. Moreover. increasing molar concentration of aqueous phosphate buffer from 0 to 0.5 M remarkably decreased the solubility. The degradation of CRY followed the apparent first-order kinetics. The degradation was accelerated with decreasing pH and increasing storage temperature. The half-lives for the degradation of CRY (1.0 mg/ml) at pH 1.28. 4.01 and 5.93 $(45^{\circ}C)$ were 2.8, 31.4 and 124 hr. respectively. The pHs of incubated solutions were to some extent lowered perhaps due to the formation of acidic degradation products. The addition of disodium edetate (0.01%) to the CRY solution (pH 4.95) retarded 2.5 times the degradation rate at $45^{\circ}C$, but the use of sodium bisulfite (0.1%) accelerated 2.9 times the rate. The activation energy for the CRY solution (20 mg/ml. pH 5.4) containing 0.01% EDTA was calculated to be 5.98 kcal/mole. When the solution was stored under nitrogen displacement in ampoule, there was no significant degradation even after 3 months at $40^{\circ}C$, indicating that protection from oxidation by air (oxygen) is essential for the complete stabilization of CRY solution.