• Biotechnology and Bioprocess Engineering:BBE
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• 제11권6호
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• pp.477-483
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• 2006

Ionic liquids in the form of organic salts are being widely used as new solvent media. In this paper three positional isomers, o-amino benzoic acid, m-amino benzoic acid, and p-amino benzoic acids were separated with four different ionic liquids as mobile phase additives using high performance liquid chromatography (HPLC). The following ionic liquids were used: 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][$BF_{4}$]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIm][$BF_{4}$]), 1-ethyl-3-methylimidazolium methylsulfate ([EMIm][MS]), and 1-octyl-3-methylimidazolium methylsulfate ([OMIm][MS]). The effects of the alkyl group length on the imidazolium ring and its counterion, and the concentrations of the ionic liquids on the retention factors and resolutions of amino benzoic acid isomers were tested. The results of the separations with ionic liquids as the eluents were better than those without ionic liquids. Excellent separations of the three isomers were achieved using 2.0-8.0 mM/L [OMIm][MS] and 1.0-8.0 mM/L [EMIm][MS] as the eluent modifiers.

• Korean Chemical Engineering Research
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• 제44권5호
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• pp.453-459
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• 2006

두 개의 D-아미노산 물질을 분리함에 있어서 이온성 액체의 영향을 고찰하였다. 아미노산 물질로서 D-tryptophan과 N-CBZ-D-phenylalanine을 사용하였으며, 이온성 액체로서 1-butyl-3-methylimidazolium tetrafluoroborate(${[BMIm]}^+{[BF_4]}^-$)을 사용하였고, 역상 액체 크로마토그래피로 분석하였다. 이동상은 각각 65％, 70％, 80％ 메탄올을 주성분으로 0.5, 1.0, 1.5, 2.0, 4.0, 6.0, 8.0, 10.0, 12.0과 15.0 mmol/L의 농도의 이온성 액체를 첨가하였고, 칼럼($3.9{\times}300mm$)에 $15{\mu}m$의 입자 크기를 가진 $C_{18}$ 실리카 겔을 충진하여 사용하였다. 이온성 액체를 첨가함으로써 D-tryptophan의 체류인자는 거의 변화가 없었지만, N-CBZ- D-phenylalanine의 체류인자는 감소하였다. 두 물질의 분리도는 메탄올의 함량과 이온성 액체의 농도에 따라 변화하였다. 메탄올의 함량이 낮을수록, 이온성 액체의 농도의 증가에 따라서 분리도는 증가하는 경향을 나타내었다

• 분석과학
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• 제19권3호
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• pp.194-202
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• 2006

중국산 천연물질인 서장채국화, 홍경천 및 장청과에서 미백성분을 추출 및 정제하였다. 잘게 분쇄한 서장채국화와 장청과 잎을 각각 물과 에틸 에테르로 추출하고 제조용 크로마토그래피 GS310 컬럼($21.5{\times}500mm$ i.d., $10-15{\mu}m$)으로 네 개 혹은 세 개의 부분으로 획득한 후 농축하였다. 잘게 분쇄한 홍경천은 메탄올로 추출하고 분석용 $C_{18}$ 컬럼 ($3.9{\times}300mm$ i.d., $15{\mu}m$)으로 2개의 부분으로 획득한 후 농축하였다. 미백효과는 in-vitro 멜라닌 생성효과로 측정하였다. 이때 사용한 멜라닌-a와 B16 셀의 농도는 $10{\mu}g/ml$이다. $200{\mu}g/ml$의 농도에서 서장채국화의 에틸 아세테이트층은 92%의 멜라닌 억제효과를 보이며, 홍경천은 60%의 멜라닌 억제효과를 보였다. 이것은 모두 알부틴의 미백효과(45.6%)보다 우수하였다. $100{\mu}g/ml$의 농도에서 장청과는 90%이상의 멜라닌 억제효과를 나타냈지만 B16흑색종 셀에 대하여 독성을 보였다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.101-102
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• 2002

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권4호
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• pp.357-363
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• 2006

Monolithic molecularly imprinted columns were designed and prepared by an in-situ thermal-initiated copolymerization technique for rapid separation of tryptophan and N- CBZ-phenylalanine enantiomers. The influence of polymerization conditions and separation conditions on the specific molecular recognition ability for enantiomers and diastereomers was investigated. The specious molecular recognition was found to be dependent on the stereo structures and the arrangement of functional groups of the imprinted molecule and the cavities in the molecularly imprinted polymer (MIP). Moreover, hydrogen bonding interactions and hydrophobic interactions played an important role in the retention and separation. Compared to conventional MIP preparation procedures, the present method is very simple, and its macroporous structure has excellent separation properties.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권1호
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• pp.52-58
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• 2004

An unstructured mathematical model for lactic acid fermentation was developed. This model was able to predict the inhibition effects of lactic acid and glucose and was con-firmed to be valid with various initial concentrations of lactic acid and glucose. Simulation of energy production was made using this mathematical model, and the relationship between the kinetics of energy metabolism and lactic acid production was also analyzed.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1163-1169
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• 2004

An unstructured mathematical model is presented for lactic acid fermentation based on the energy balance. The proposed model reflects the energy metabolic state and then predicts the cell growth, lactic acid production, and glucose consumption rates by relating the above rates with the energy metabolic rate. Fermentation experiments were conducted under various initial lactic acid concentrations of 0, 30, 50, 70, and 90 g/l. Also, a genetic algorithm was used for further optimization of the model parameters and included the operations of coding, initialization, hybridization, mutation, decoding, fitness calculation, selection, and reproduction exerted on individuals (or chromosomes) in a population. The simulation results showed a good fit between the model prediction and the experimental data. The genetic algorithm proved to be useful for model parameter optimization, suggesting wider applications in the field of biological engineering.

• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.292-296
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• 1999

The high density mixed mode adsorbent known by the trade name of Mimo-AD was used to purify lysozyme directly from the hen egg white (HEW). The homogenized hen egg white was treated with the adsorbent in a stirred vessel for lysozyme adsorption, and then the adsorbent, easily separated from the HEW by sedimentation, was packed into a column. The remaining HEW and contaminant proteins were removed by washing with pH 11 distilled water in an expanded-bed state, and subsequently the elution was performed with pH 12 distilled water in a packed-bed state. By this simple and rapid adsorption, washing, and elution procedure, lysozyme was purified to＞95％ with an overall recovery yield of 66％. This process offers a great potential for industrial application by allowing the extraction of lysozyme while retaining the commercial value of HEW.

• Journal of Microbiology
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• 제41권2호
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• pp.165-168
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• 2003

We report a new PCNB-degrading strain (PCNB-2) that is able to utilize and grow on PCNB (100 ppm) as a sole carbon source. This strain was identified as Alcaligenes xylosoxidans based upon 16S rDNA sequence analysis, API 20 NE tests and cell membrane lipid analysis. The new PCNB degrader Alcaligenes xylosoxidans PCNB-2 could find use in bioremediation of PCNB, which is environmentally persistent.

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.979-984
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• 2008

In this study, 8 solutes (aniline, caffeine, p-cresol, ethyl benzene, methylparaben, phenol, pyridine, and toluene) have been tested in terms of linear solvation energy relationships (LSER). Several micellar liquid chromatography (MLC) systems using cationic surfactant cetyltrimethylammonium bromide (CTAB) and a mixture of water with (methanol, n-propanol, and n-butanol) modifiers were characterized using the LSER solvation parameter model. The effects of the surfactant and modifier concentration on the retention in MLC were discussed. LSER model had demonstrated high potential to predict retention factors with high squared correlation coefficients ($r^2$ > 0.99). A comparison of predicted and experimental retention factors suggests that LSER formalism is able to reproduce adequately the experimental retention factors of the solutes studied in the different experimental conditions investigated. This model is a helpful tool to understand the solute-surfactant interactions and evaluate the retention characteristic of micellar liquid chromatography.