• Microbiology and Biotechnology Letters
• /
• v.28 no.4
• /
• pp.223-227
• /
• 2000

A novel two-step acetone treatment method was developed to enhance the enantioselectivity of Candida rugosa lipase (CRL) toward the hydrolysis of racemic naproxen methyl ester. The acetone-teated CRL was considerably more enantioselective than the crude CRL, yielding an enantiomeric excess of 98~100%. The crude and acetone-treated CRLs were subjected to anion exchange chromatography, and their chromatography profiles were compared. In consequence, both chromatography profiles were found to be almost identical, resulting in two separate lipase peaks (lipase A and B). The lipase B, which is known to be less enantioselective, was treated with acetone using a two-step treatment method. The enantioselectivity of acetone-treated lipase B was dramatically increased, yielding an enantiomeric excess of 99%.

• Journal of the Korean Applied Science and Technology
• /
• v.6 no.2
• /
• pp.53-58
• /
• 1989

A series of four sodium ${\alpha}-sulfo$ fatty acid allylester oligomers such as sodium ${\alpha}-sulfo$ lauric acid allylester oligomer, sodium ${\alpha}-sulfo$ myristic acid allyl ester oligomer, sodium ${\alpha}-sulfo$ palmitic acid allyl ester oligomer and sodum ${\alpha}-sulfo$ stearic acid allyl ester oligomer were examined for surface tension, defloculation effect and emulsifying power. Also critical micelle concentration (cmc) was evaluated. Consequently, these sodium allyl ${\alpha}-sulfo$ aliphatic carboxylate aligomers show o/w type emulsifying agent and dispersion effect in 1g/100ml soulution.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.81-81
• /
• 2010

This paper presents results of experimental investigations on natural ester regarding the breakdown strength. Aging of insulating material in a pole transformer has been studied by performing accelerated thermal aging test. Sealed aging test vessels containing copper, laminated core, Krapt paper and insulating oil(Natural oil and Mineral oil) were aged at $140^{\circ}C$ for 30days. Compared to the conventional transformer oil, electric property of the natural ester fluid is excellent.

• Journal of Pharmaceutical Investigation
• /
• v.19 no.1
• /
• pp.21-27
• /
• 1989

Kinetic and thermodynamic aspects of the interface transfer of cefoperazone and its pivaloyloxymethyl ester were studied in a two-phase system composed of aqueous buffers and n-octanol by using the absolute reaction rate theory. In terms of the net thermodynamic parameters for the process, ${\Delta}S$ increased and ${\Delta}F$ decreased as the lipophilicity increased. With the increased ratio of forward $(k_f)$ to backward rate constants $(k_b)$, the ester was more lipophilic than cefoperazone, but the aqueous solubility was reduced.

• Textile Coloration and Finishing
• /
• v.3 no.1
• /
• pp.28-36
• /
• 1991

Thermotropic behavior was observed in a number of aromatic copoly (ester amide)s containing a flexible spacer based on 4,4'$-dicarboxyalpha,\varpi-diphenoxy$ alkanes as an A component, di-acetylated p-aminophenol as a B, di-acetylated hydroquinone as a C gave the thermotropic copoly (ester amide)s containing a flexible spacer in the polymer backbone. 4,4'-diamino-3,3'-dimethoxybiphenyl as an amino group containing monomer as a D components. In the last case, up to 60 mol% of amide group was allowed to afford thermotropic liquid-crystallinity. The polymer structure and thermotropic nature were examined by solid-state and solution $^{13}C$ NMR spectroscopy, differential scanning calorimeter, polarizing microscopy, and IR spectroscopy.

• Journal of the Korean Chemical Society
• /
• v.35 no.3
• /
• pp.249-252
• /
• 1991

Two new metabolites have been characterized from the methylene chloride extracts of Bezoar Bovis, a well known oriental drug : 8-octadecenoic methyl ester and cholesta-3,5-diene. Their structures were deduced from $^1$H-NMR and GC-mass spectra.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
• /
• 2004.05a
• /
• pp.334-336
• /
• 2004

This study was carried out to investigate the effect of phytosterol ester addition on lowering blood cholesterol in cholesterol-reduced Cheddar cheese, which was manufactured by the mixture of cholesterol-reduced cream and skim milk. After the cholesterol reduction process by ${\beta}$-CD treatment, the cholesterol removal rate was in the range of 91.2 to 92.1%. In animal study, 18% of total blood cholesterol was lowered in 8% phytosterol ester-added Cheddar cheese, which was significantly different from that of control. The present study indicated that phytosterol ester addition showed a profound lowering effect of blood with cholesterol-reduced Cheddar cheese.

• Journal of Applied Biological Chemistry
• /
• v.43 no.4
• /
• pp.264-268
• /
• 2000

High activity of acidic ethylacetate extract from the culture supernatant of ginseng growth-promoting bacterium Pseudomonas fluorescens KGPP 207 and its fractions were demonstrated through wheat coleoptile bioassay. The following auxins and auxin-like compounds were identified in these fractions by combined gas chromatography-mass spectrometry: indole-3-acetic acid, indole-3-acetic acid methyl and ethyl ester, indole-3-butyric acid, indole-3-lactic acid and its methyl ester, indole-3-propionic acid, indole-3-pyruvic acid, p-hydroxyphenyl acetic acid, p-hydroxyphenyl acetic acid methyl and ethyl ester, phenyl acetic acid and its methyl ester. The bacterium KGPP 207 belongs to the strain of P. fluorescens which produces plant growth regulators and its beneficial effect on the ginseng growth may be due to the formation of the identified compounds.

• Journal of the Korean Applied Science and Technology
• /
• v.6 no.1
• /
• pp.21-26
• /
• 1989

Four fatty acid vinyl esters were synthesized by transesterification between vinyl acetate and lauric acid, myristic acid, palmitic acid, stearic acid, respectively. Fatty acid vinyl ester oligomers were prepared from polymerization of four fatty acid vinyl esters in the presence of potassium persulfate in methanol. The ${\alpha}-sulfonation$ of these four fatty acid vinyl ester oligomer were carried by direct addition of sulfur trioxide. Especially, molecular weights of sodium ${\alpha}-sulfo$ fatty acid vinyl ester oligomers were measured by boiling point method.

• Journal of the Korean Chemical Society
• /
• v.38 no.7
• /
• pp.516-520
• /
• 1994

New synthetic method of optically active 2-amino-3-phosphonopropionic acid from L-serine was developed and their phosphonotripeptides, phthalylglycylglycyl-2-amino-3-(diethylphosphono)-propionic acid methyl ester and phthalylglycyl-L-phenylalanyl-2-amino-3-(diethylphosphono)propionic acid methyl ester, were synthesized by coupling reaction of amino acids with 2-amino-3-phosphonopropionic acid methyl ester.