• KSBB Journal
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• v.18 no.6
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• pp.529-535
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• 2003

We studied degradation effects of hydrophobic substrate such as kerosene and diesel by adding a biosurfactant originated from Pseudomonas aeruginosa F722 and chemical surfactants (Tween 80 and detergent) with aeration. The surface tensions of the biosurfactant, Tween 80 and detergent were 30mN/m, 39mN/m and 31mN/m, respectively. When the concentration of biosurfactant added in C-medium was 0.01 and 0.15%(w/v), the ratios of hydrocarbon degradation were 94.3％ and 94.2% respectively. It was 6.2%(w/v) higher than when the concentrations of added biosurfactant were 0.05, 0.1 and 0.2％. The degradation ratios of the chemical surfactants (Tween 80 and detergent) were 94.5％ and 93.5％ respectively. The effects of the biosurfactant and chemical surfactants were similar on the degradation ratio in mixtures of kerosene and diesel. However, the population of viable p. aeruginosa F722 at the end of the cultivation period was twice as higher in the biosurfactant than that in the chemical surfactant. We also studied the effect of aeration (0.5vvm) on the degradation ratio. The biosurfactant addition experiment was conducted with 0.5vvm air, 35$^{\circ}C$, 150rpm, pH 8.0, 3days, 1.0% (w/v) substrate. When p. aeruginosa F722 and 0.15%(w/v) biosurfactant were added, the degradation ratio of hydrocarbon was 94.8％. Without p. aeruginosa F722, it was 68%. Thus, with aeration, the degradation ratio of hydrocarbon was increased by 26.8％. In addition, the cultivation time was shortened by 1/3. The degradation ratios of hydrocarbon in shaking culture (cultivation time; 3days) and stationary culture (cultivation time; 10days) were 94.8 and 93.7％ respectively. Thus, the addition of biosurfactant and aeration enhanced the degradation of hydrocarbon originated kerosene and diesel.

• Journal of Sericultural and Entomological Science
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• v.17 no.2
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• pp.155-160
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• 1975

The study was carried out to investigate the effects of various compositions of artificial diet for silkworms on the cocoon shell fibroin-hydrolyzing with the proteolytic enzyme. The obtained results are summarized as follows： 1. It was found that the fibroin-hydrolyzing ratio of the cocoon shell made by silkworms fed with artificial diets was lower than that of the cocoon shell made by silkworms fed with natural diet (mulberry leaf) 2. The amount of soybean meal in the artificial diet was negatively related to the sericin content of cocoon shell but it scarcely affected on the fibroin-hydrolyzing ratio. 3. The increase of sucrose in the artificial diet reduced the sericin content of cocoon shell but it didn't influence on the fibroin-hydrolyzing ratio. 4. A significant difference between male and female silkworms fed with artificial diets was found in the sericin content of cocoon shell but it was not approved in tile fibroin-hydrolyzing ratio. 5. The artificial diet containing 8 per cent of mulberry leaf powder increased the fbroin-hydrolyzing ratio more than that containing 10 per cent of mulberry leaf powder or that containing 8 per cent of mulberry leaf powder and a little of methionine did. 6. The artificial diet for all instars of silkworms increased the fibroin-hydrolyzing ratio more than the artificial diet for 1st to 3rd instars and natural diet (mulberry leaf) for the rest instars did.

• Journal of the Korean Wood Science and Technology
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• v.38 no.6
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• pp.568-578
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• 2010

In this study, the possibility of biodegradation of polychlorinated biphenyls (PCBs) by various white rot fungi was evaluated, and outstanding white rot fungi for the degradation of PCBs were selected. Seven white rot fungi were used to degrade Aroclor 1254 and 1260, which are widely considered to be toxic and difficult to degrade. And the degradation rates of Aroclors by selected white rot fungi were performed by GC analysis. Through the resistance test of white rot fungi on different concentrations of PCBs, the inhibition of mycelial growth of Cystidodontia isubellina was much less than that of others, and this fungus grew faster than others, relatively. Based on this result, it was considered that C. isubellina was selected as degrading fungus for Aroclors. As a result of biodegradation rate of Aroclors by Cystidodontia isubellina, the degradation rate of Arolor 1254 was reached to 57.57% in 13 days, which showed very high degradation rate. Also the degradation rate of Aroclor 1260 by C. isubellina had a tendency of increasing along with increasing incubation day. Maximal degradation rate of Aroclor 1260 was 49.43% at 13 days. Based on this results, it indicated that in comparison with a previous study, high degradation rate was obtained by C. isubellina.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.525-528
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• 2006

아임계 및 초임계수에 의한 목질바이오매스의 당화특성을 분석하기 위하여 분해공정 동안 압력을 23MPa(물의 임계압력)로 고정하고 물의 아임계 온도$(325^{\circ}C,\;350^{\circ}C)$와 초임계 온도$(380^{\circ}C,\;400^{\circ}C,\;425^{\circ}C)$에서 현사시나무 목분을 각각 60초 동안 처리하였다. 생성된 현사시나무의 분해산물에는 액상과 고형분의 분해산물이 섞여 있었다. 각 처리조건에 따른 목질바이오매스의 분해율은 온도가 상승함에 따라 증가하였으며 초임계 온도인 $425^{\circ}C$에서 최고 83.1%의 분해율을 나타냈다. 아임계 및 초임계수에 의해서 생성된 단당류는 고성능 음이온 교환 크로바토그래프(HPAEC)를 이용하여 분석하였다. 목질바이오매스의 초임계수 분해과정에서 처리 온도가 높아지면서 단당류 수율은 증가하는 경향을 보였으며, $425^{\circ}C$에서 가장 높은 7.3%의 단당류 수율을 나타내었다. 아임계 온도 범위에서는 현사시나무의 섬유소 성분 중에서 자일란이 우선적으로 분해되어 자일로스의 생성비율이 비교적 높았으며, 처리온도가 높아지면서 셀롤로오스의 분해에 의한 글루코오스 생성율이 급격히 상승하였다. 이렇게 생성된 단당류 성분들은 고온의 반응조건하에서 열분해 반응에 의해서 더욱 분해되어 퓨란계 화합물로 변형되었다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.42-46
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• 2003

This research was carried out for searching the treatment conditions of organic acid and heating to prepare oligomers from the carrageenan. The applied treatments were autoclaving, micraowaving, and ultrasonicating with acetate, citrate, lactate, malate, and succinate. Among several physical depolymerization methods, auo-claving treatment was the most effective for hydrolyzing the carrageenan to low molecular compounds such as oligosaccharides. Citrate or malate was the most effective catalyst in hydrolyzing carrageenan to some oligo-saccharides among 5~7 different organic acids. An acceptable autoclaving condition for hydrolyzing carrageenan to oligosaccharides was to treat for 120 min at 110~12$0^{\circ}C$. The maximum depolymerization ratio produced by autoclaving was about 23.0%. The depolymerized carrageenan prepared by autoclaving at 12$0^{\circ}C$ had oligo-saccharides of 5~7 species.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.257-260
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• 2000

본 연구에서는 유한용량을 갖는 조립/분해 생산시스템의 산출율분석을 위한 근사적 방법을 제시한다. 유한용량을 갖는 조립/분해 생산시스템은 상태공간이 매우 크기 때문에 효율적으로 분석하기가 어렵다. 따라서 근사적 방법에서는 조립/분해 생산시스템을 비교적 작은 규모의 상태공간을 갖도록 단순 조런/분해 시스템과 단일 직렬시스템을 갖는 각각의 부분시스템으로 분해한다. 각 부분시스템은 2차 모멘트가 고려된 PH/Ph/1/C 시스템으로 기술되고 수리적 방법에 의해 분석되어진다. 실험결과는 시뮬레이션과 비교되고, 제시된 근사적 방법이 효과적이라는 것을 보여준다.

• Journal of the Korea Safety Management & Science
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• v.12 no.3
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• pp.135-143
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• 2010

본 연구에서는 대기오염물질인 유해 황산화물 가스를 이산화티탄 촉매 반응기와 연면 방전 반응기를 조합한 반응기에서 플라즈마 방전반응에 의하여 주파수 변화, 체류시간, 전극의 굵기, 첨가 모의가스 등의 공정 변수를 변화 시켜 분해제거 실험을 하였다. 실험 결과 황산화물의 분해제거 실험에서 주파수 10kHz에서 소비전력 19W에서 분해제거율은 99%이었으며 이산화티탄 촉매반응기를 부착한 경우가 없는 경우보다 5%이상 증가효과가 이었다. 첨가가스로 메탄을 첨가한 경우 분해제거율이 증가하였고, 산소농도가 높아질수록 증가하였다 또한 이산화 탄소를 첨가한 경우 분해율은 감소하였다.

• 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.

• Journal of Sericultural and Entomological Science
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• v.18 no.1
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• pp.21-26
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• 1976

The study was carried out to investigate the variations in the fibroin hydrolysis of different cocoon shell layers, and the relationship between the hydrolysis and silk physical property. The obtained results are as follows: 1. The fibroin hydrolyzing ratio was highest at the inner layer of cocoon shell and. next in order. at the middle layer and at the outer layer. 2. The fibroin hydrolyzing ratio of abnormal cocoons was higher than normal cocoon and it was different among them, tile highest was double coroon, thin shell cocoon and perforated cocoon in order. 3. The sericin content and fibroin hydrolyzing ratio of Jam 111 and Jam 112 was higher than that of Jam 111 $\times$ Jam 112. 4. The fibroin hydroiyzing ratio of the cocoons fed with the artificial diets was increased at the inner layer. The sericin content of those lessened at the inner layer, however, it slightly increased at the most inner layer more than at the inner layer. 5. The breaking strength of the degummed silk fiber of different cocoon layers was reduced at the inner layer. The breaking Strength of abnormal silk fiber was less than that of normal silk fiber. 6. A negative correlation (r= －0.8) )was approved between fibroin hydrolyzing ratio and breaking strength of silk fiber, and the regression line was Y=－0.29x＋5.07.

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.311-318
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• 1994

We examined spatial and temporal patterns of root decomposition for three and half years, from October 1986 to April 1990, in semi-arid Chihuahuan Desert. Decomposition of roots occurred in a two-phased pattern: an early period of rapid mass loss followed by a period of slower loss. The rate of root decomposition had a high negative correlation with the initial lignin concentration in roots (r=-0.84, p<0.05). Annual mass loss rate of Baileya multiradiata, a herbaceous annual, was the highest with the value of 0.60, while that of Panicum obtusum. a perennial grass which was restricted to playa, was the lowest with 0.13. The mass loss rate of roots in the playa was the lowest among the vegetation zones along the transect. After 42 months elapsed, fluffgrass roots in playa lost 40% of the initial mass, while in other sites it lost on average 55% of the initial mass. In all roots except for desert marigold, there was an initial release of nitrogen early in decomposition followed by net nitrogen immobilization. Nitrogen concentration of the desert marigold roots showed linear increase from the beginning. Lignin concentration of perennial grass roots were higher than those of herbaceous annual and woody perennial root.