• Journal of Microbiology and Biotechnology
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• v.8 no.2
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• pp.165-170
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• 1998

Lipase-catalyzed esterification of n-butyl oleate was carried out in n-hexane as a model reaction. The optimal activity of Candida rugosa lipase was shown in a water activity ($a_w$) range of 0.52 to 0.65 at $30^{\circ}C$. The water produced from the esterification was removed by a tubular type pervaporation system. The rate of ester formed from the enzymatic esterification was allowed to be the same as the rate of water removal by maintaining an optimal $a_w$ of the reaction system using an on-off dewatering control device. The reaction rate and yield with a$a_w$ control were increased two folds higher than the respective values for the uncontrolled reaction.

• Journal of Acupuncture Research
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• v.28 no.2
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• pp.89-95
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• 2011

Objectives : The purpose of this study was to investigate the composition of Rehmannia glutinosa's essential oils with Rehmanniae Radix herbal acupuncture Methods : I obtained the essential oils of Rehmannia Radix by hydrodistillation extraction method and supercritical fluid extraction(SFE) method, and then I analyzed those by GC/MS(gas chromatography/mass spectrum). Results : 1. With GC(gas chromatography) and GC/MS(gas chromatography/mass spectrum) analysis. I identified 9 compounds in the Rehmanniae Radix's essential oil obtained through the SFE method. The main compounds were as follows : Hexachloroethane(2.24%), N-Butyl-benzenesulfonamide(2.05%), hexadecanoic acid(1.93%), hexadecanoic acid, ethyl ester(3.49%), 9,12-Octadecadienoic acid(z,z)(2.70%), (9E)-9-Octadecenoic acid(6.14%), ethyl linoleate(4.43%), ethyl oleate(5.80%). 2. I failed to get Rehmanniae Radix's essential oil obtained through the hydrodistillation method. 3. With GC(gas chromatography) and GC/MS(gas chromatography/mass spectrum) analysis. I identified 4 compounds in the Rehmanniae Radix's essential oil obtained through the hydrodistillation method. The main compounds were as follows : Ethylbis(trimethylsilyl)amine(1.04%), 2-(Trimethylsiloxy)benzoic methyl ester(2.65%), Hexadecanoic acid trimethylsilyl ester(12.61%), octadecanoic acid, trimethylsilyl ester(6.28%). Conclusions : The substances by hydrodistillation method may not perfectly match with the substances by supercritical fluid extraction(SFE) method in essential oils extracted form Rehmanniae Radix. But, the main substances was assumed Hexadecanoic acid and octadecanoic acid.