• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.508-508
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• 1986

이온성 계면활성제 존재하에서 유기용매에 물을 첨가하면 물이 계면활성제에 약해 둘러싸이면서 유기용매에 용해되어 의사 이상계가 형성된다. 이러한 계를 역미셀 또는 W/O microemulsion이라고 하며 계면활성제로 둘러 쌓인 물분자 집하체를 water pool이라고 한다. 그런데, 10여년 전 water pool에 bipolymer를 용해시킬 수 있다는 사실이 밟혀짐에 따라 이러한 체계를 생체막을 단순화시킨 모형막으로서 막을 통해 일어나는 여러 가지 현상의 규명에 이용하거나 물에 불용성인 기질의 효소 촉매반응의 반응계로 이용하는 연구가 꾸준히 이루어져 있다. 본 강연은 역미셀계에 리파제를 용해시켜 유지의 가수분해를 유도함으로써 지방산을 생산하는 방법에 관한 연구이다. 역미셀계에서 리파제의 특성은 에멀전계와 비교했을 때 큰 차이가 없었으며 물과 계면활성제의 몰 비율(R값)은 효소의 초기반응 속도에 커다란 영향을 끼치는 인자로 나타났다. 올리브유 농도가 5%(v/v), AOT농도가 0.1M, 초기 물 농도가 1.0M의 조건에서 유지의 회분식 가수분해 실험을 행한 결과 이 기질은 거의 완전히 가수분해되었으며, 이 반응계에서 R값과 초기 물 농도는 반응의 평형에 커다란 영향을 끼치는 것으로 나타났는데 초기 물 농도가 증가할수록 평형 가수분해율은 증가하였단 이러한 결과를 반응속도론 측면에서 분석한 결과 역미셀계에서 리파제 반응은 에멀전계에서와는 달리 2차 반응을 따르는 것으로 나타났다. 물 농도가 평형 가수 분해율과 속도 변수에 끼치는 영향을 수학적으로 표시하기 위하여 2차 가역적 반응 속도론에 근거하여 가수분해율, 평형상수, 속도상수 둥을 나타내는 식을 유도하였고 이를 바탕으로 여러 가지 실험 조건 하에서 리파제 반응의 반응 시간에 따른 가수분해율을 예측한 결과는 실제 실험 결과와 잘 일치하였다(편차는 5%). 또한 속도상수와 R값과의 관계식 및 유도한 방정식을 이용하여 추정한 초기속도와 평형 가수분해율을 최대화하는 R값은 각각 10.4 와 11.4 였다.

• Microbiology and Biotechnology Letters
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• v.15 no.2
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• pp.98-103
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• 1987

Two phase reaction system was used to hydrolyze the olive oil for fat splitting. Kinetics of lipases in two phase system were investigated by determining the hydrolysis rate of triglycerides at various olive oil concentrations in isooctane using the microbial lipases from Candida rugosa and Rhizopus arrhizus. The rate equation in lipid hydrolysis for various olive oil concentrations in two phase system was deviated from the Michaelis-Menten kinetics. The results suggested that the olive oil concentration in isooctane affects the interfacial area. The dependency of the interfacial area on olive oil concentration is greater at the lower olive oil concentration than at the higher substrate concentration. We modified the rate equation by considering the interfacial area between two phases depending on the olive oil concentration in solvent phase.

• Microbiology and Biotechnology Letters
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• v.33 no.1
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• pp.29-34
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• 2005

Lipase-producing bacteria (S3) were isolated from intertidal flat at Saemanguem. A isolated strain was identified as Psychrobacter species by physiological and fermentational characterization as well as 16S rRNA analysis. The strain was then named as Psychrobacter sp. S3. P. sp. S3 grew most rapidly at $30^{\circ}C$, but grew well even at $10^{\circ}C$ and its lipase activity was most high when cultivated at $20^{\circ}C$. Lipase S3 had optimum temperature of $30^{\circ}C$ for the hydrolysis of p-nitrophenyl caproate and had more than $80^{\circ}C$ activity even at $10^{\circ}C$. The activation energy was calculated to be 1.5 kcal/mol, which showed that it was a typical cold-adapted enzyme. It was an alkaline enzyme with optimum pH of $9.0\~9.5$. It could hydrolyze various length of triglycerides. Among them, it hydrolyzed most rapidly $C_4,\;C_{14},\; C_{16}-length$ triglycerides. When added to tributyrin-agarose gel, lipase S3 hydrolyzed tributyrin most rapidly at 30 and $40^{\circ}C$, but it could hydrolyze well even at $4^{\circ}C$.

• Journal of the Korean Chemical Society
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• v.52 no.5
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• pp.488-494
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• 2008

• Applied Chemistry for Engineering
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• v.20 no.4
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• pp.443-448
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• 2009

It is known that 1,3-diglyceride (1,3-DG) hardly accumulates inside human body because the metabolism of 1,3-DG is entirely different from that of general fats such as triglycerides (TG). This research focuses on the selective synthesis of 1,3-DG by the esterification reaction using an immobilized lipase. For a reaction between glycerin and oleic acid (OA) with a mole ratio of 1 : 2 under vacuum, changes in the compositions of monoglyceride (MG), TG and DG and the contents of 1,3-isomers in DG were investigated, as a function of reaction temperature and the amount of lipase. The reactivities determined by the rate of the consumption of OA became higher with increased in temperature and the amount of lipase. Changes in the compositions of MG, DG and TG, however, occurred after the DG content reached maximum, which were found to be dependent on various factors. TG was a main product, and significant decrease in the amount of both 1,3-DG and DG were observed, when reactions were carried out at high temperatures or when 10 wt% of lipase was used.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.762-768
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• 1988

The lipolytic enzyme of milk from hormone treated and non treated cows was isolated and purified, It was shown that the crude lipase extract from the milk before and after a hormone treatment of the cows was different in color, foaming properties, yield and specific activity. Final purification of the lipase system was achieved by affinity chromatography on Heparin-Sepharose CL-6B. The lipase bound by Heparin-Sepharose was then characterised. The pH-optimum of the purified enzyme was 8.5 for butteroil emulsion as a substrate and the optimum temperature was $30^{\circ}C$ respectively. The molecular weight. determined by SDS-polyacrylamidegel electrophoresis, was about 70,000. The activity increased by 10% hen 0.01% bovine serum albumin was added to the substrate. The results indicate the enzymes obtained by affinity chromatography from milk before and after hormone treatment had the similar characteristics. The second lipolytic active component that was not bound by Heparin-Sepharose must be the cause of spontaneous rancidity.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.206-214
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• 1990

Effects of commercial food grade porcine pancreatic lipase on the neutral volatile compounds in Cheddar cheese were studied The enzyme was incorporated into the cheese at two different levels of concentration and ripened at various temperatures. The production of 2-butanone increased at higher amount of lipase and higher temperature, but the production of 2-pentanone was inconsistent trends during ripening periods. The concentration of acetaldehyde was the highest among aldehydes and was increased consistently during ripening Periods. In alcohol production ethanol was the most abundant but no further consistent trend was observed after 6 wk. The production of ethyl butyrate was the most abundant ester and related io lipase activities as well as ripening temperatures. Dimethyl sulfide was the only sulfur compound and appeared not to be related to the addition of lipase or ripening temperatures . Statistical analysis suggested that ethyl butyrate was most correlated to aged Cheddar flavor during cheese ripening.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.248-254
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• 1990

Commercial food grade porcine-pancreatic lipase was incorporated into cheese at two different levels of concentration and ripened at $7^{\circ},\;13^{\circ}\;and\;21^{\circ}C$ Gas chromatographic analysis showed that the pancreatic lipase-treated cheese produced significantly higher levels of short-chain free fatty acids than controls. At $21^{\circ}C$ the high level of pancreatic lipase-treated cheese produced medium flavor cheese at 1 wk and close to sharp flavor cheese at 3 wk without causing distinctive defects. The low level of pancreatic lipase-treated cheese developed a number of good quality cheese. They were roughly equivalent to medium and sharp cheeses when ripened at $7^{\circ},\;13^{\circ}\;and\;21^{\circ}C$ for 3 to 15wk. Statistical analyses indicated that there were significant correlations between aged Cheddar flavor and the concentration of c6 as individual short chain free fatty acids (FFA) or C4 and C6 FFA combinations. Pancreatic lipase may be applicable for the accelerated ripening of Cheddar cheese if appropriate conditions are used.

• Korean Journal of Food Science and Technology
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• v.17 no.6
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• pp.490-494
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• 1985

The effect of organic solvents on the stability and catalytic activity of the microbial lipase from Rhizopus arrhizus for interesterification of fats and oils has been examined. The reaction system used was nonaqueous solvent system (two phase system). The solvents examined were 5 hydrocarbons (n-hexane, n-heptane, n-octane, isooctane, and cyclohexane) and 3 ethers (diethylether, diisopropylether, di-n-butylether). The results revealed that diisopropylether and isooctane are superior to the other solvents examined for interesterification of fats and oils in two phase systems.

• Bioindustry News
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• v.12 no.3
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• pp.8-18
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• 1999