• Journal of the Korean Institute of Intelligent Systems
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• v.3 no.3
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• pp.3-18
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• 1993

본 논문에서는 박테리아에서 생성되는 생체 계면활성제인 emulsan의 생산을 위한 유가식 배양에서 에칸을 농도의 제어에 퍼지기법을 적용하였다. 기절저해가 있는 유가식 배양에서 emulsan의 생산을 향상시키기 위해 최대 비성장속도를 갖는 최적 기질농도가 유지되도록 기질인 에탄올의 공급 속도가 조절되어 졌다. 생물반응기에서 Acunetobacter calcoaceticus RAG-1 박테리아를 회분식과 유가식으로 배양 실험하여 최적 에탄올 농도를 구하고, kinetic 모델을 제시하였다. 배양실험의 결과와 지식을 바탕으로 퍼지 규칙을 구성하였다. 퍼지 제어기에서 제어 입력변수는 기질농도의 최적치와 운전치의 오차와 오차의 변화로서 구성되고, 제어 출력변수는 기질 공급 속도의 변화량으로 구성되었다. 멤버쉽 함수를 입력변수의 퍼지 집합화 과정을 통하여 구하였고, 최소-최대법과 무게 중심법을 이용하여 출력 제어값을 구하였다. 유가식 배양의 전산모사와 실험 결과에서 퍼지제어 기법은 최적 기질 농도를 정확히 제어하였으며, emulsan 생산은 향상되었다.

• Applied Biological Chemistry
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• v.38 no.3
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• pp.248-253
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• 1995

Optimum conditions for the enzymatic hydrolysis of isolated sesame meal protein were investigated. Optimum conditions by papain were $60^{\circ}C$, pH 6.0, 3% enzyme concentration to substrate and 1.5% substrate concentration, respectively. The optimum operating conditions using pepsin were $55^{\circ}C$, pH 9.0, 3% enzyme concentration to substrate and 1% substrate concentration. The optimum operating conditions using trypsin were $60^{\circ}C$, pH 9.0, 1% enzyme concentration to substrate and 1% substrate concentration.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.351-354
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• 2002

This research discussed about the substrate transport phenomena in anaerobic biofilm. Three anaerobic fixed biofilm reactors were filled with the sludge of anaerobic digestor from Suyoung wastewater treatment plant. After 15 days of biofilm formation periods, suspended solids within the reactors were removed, and each fixed biofilm reactor was supplied with synthetic wastewater of different concentration of 8.00 mgTOC/L, 9.76 mgTOC/L and 18.97 mgTOC/L, respectively. The experimental results in conjunction with substrate transfer phenomena indicated that data - thickness, substrate removal rate. At the low influent substrate concentration(reactor 1 : 8.00 mgTOC/L, reactor 2 : 9.76 mgTOC/L), the rate of substrate utilization($k_v$), effective diffusivity($D_{eff}$) of substrate in biofilm were similar. While $k_v$ and $D_{eff}$ of the high influent substrate concentration(reactor 3 : 18.97 mgTOC/L) were higher than data in the reactors of the low influent substrate concentration.

• Applied Biological Chemistry
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• v.35 no.6
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• pp.501-506
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• 1992

Pepsin-catalyzed hydrolysis and plastein reaction were carried out to prepare plastein product from soymilk residue protein. Conditions required for optimal hydrolysis of soymilk residue protein and subsequent plastein production were investigated. The optimum substrate concentration, enzyme-substrate ratio, pH, reaction temperature and incubation time for hydrolysis were 3%, 1/50, 1.7, $45^{\circ}C$ and 24 hours, respectively. Plastein formation from peptic hydrolysate of soymilk residue protein was most effective at substrate concentratin of 40%, pH 4 and $45^{\circ}C$. Reaction time of 18 hours and enzyme-substrate ratio of 1/100 were selected for plastein production. Electrophoresis of the products revealed that protein-like substances of high molecular weight were produced from the plastein reaction.

• KSBB Journal
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• v.14 no.6
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• pp.639-642
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• 1999

Optimization of the chitosanoligosaccharide production was studied with chitosanase. The optimum conditions for the enzymic reaction have been determined. Enzyme stability was maintained above 90% after 6 days at pH 5.0. The optimum initial reaction rate was appeared in 1.0% of chitosan solution. The production yield of chitosanoligosaccharides was over at 0.4%~2.0% of chitosan. At 4.0% of chitosan solution, however, the production yield was decreased to 64.6%. To increase the yield, stepwise addition of substrate into the reactor was investigated. In this case, the yield was increased from 64.6% to 83.2% and the final concentrations of chitosanoligosaccharide was 12.26 mg/mL. By TLC analysis, most of the chitosanoligosaccharides produced were 3-5 mers.

• Journal of the Korean Society for Railway
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• v.11 no.4
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• pp.378-383
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• 2008

In December 2006, the Ministry of Environment Republic of Korea established the guideline which is "Indoor Air Quality Management Guidelines in Public Transportation." as control items, $CO_2$ (carbon dioxide) and PM10 (particle matter) are classified two categories, that is, Level 1 (non-rush hour), Level 2 (rush hour). Therefore, the quality of air in train and subway should be controlled in accordance with the guideline. We took a measure the air freshness inside train twice at Line 4 (Tangogae-Oido), in Sep. 2007 and at Line 1 (Dongincheon-Yongsan) in Nov. 2007, respectively and, also expected the emitted $CO_2$ concentration by using a property of matter such as EMU (Electric Multiple Unit) design reviewing specification and air. According to the measured values, the concentration of PM10 was 44, 57, 45% and the concentration of $CO_2$ was 39, 36, 44% respectively, all measured values are within the guideline and also, as a result we found the expected value and measured value are similar.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.41-49
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• 2023

This study examined the effect of input substrate concentration on hydrogen production of microbial electrolysis cells. To compare the performance of MEC according to the input substrate concentration, six laboratory-scale MEC reactors were operated by sequentially increasing the input substrate concentration from 2 g/L of sodium acetate, to 4 g/L, and 6 g/L. The current density, hydrogen production, and SCOD removal rate were analyzed, and energy efficiency and cathodic hydrogen recovery were calculated to compare the performance of MEC. The maximum volumetric current density was obtained at 4 g/L condition (76.3 A/m³) and it decreased to 19.0 A/m³, when the input concentration was increased to 6 g/L, which was a 75% decrease compared to the 4 g/L input condition. Maximum hydrogen production was obtained also at 4 g/L condition (47.3 ± 16.8 mL), but maximum hydrogen yield was obtained at 2 g/L input condition (1.1 L H₂/g COD_in). Energy efficiencies were also highest in 2 g/L condition; the lowest result was observed at 6 g/L condition. Maximum electrical energy efficiency was 76.4%, and the maximum overall energy efficiency was 39.7% at 2 g/L condition. However, when the substrate concentration increased to 6 g/L, the performance was drastically decreased. Cathodic hydrogen recovery also showed a similar tendency with energy efficiency, with the lowest concentration condition showing the best performance. It can be concluded that operating at low input substrate concentration might be better when considering not only hydrogen yield but also energy efficiency.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.13-16
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• 1989

Attempts were made to fix acetaldehyde on base materials, which were selected from carbohydrates, by freeze drying. More acetaldehyde was fixed, in general, on combined base materials than single base materials, and mannitol+lactose were the best among the combined base materials tested. But the combination of mannitol and maltodextrin appeared to be more economical for the mass production. Loss of acetaldehyde during freeze drying was decreased as the concentration of the combined base material was increased, and it reached minimum at 40% of the base material. As dryer chamber pressure was reduced, loss of acetaldehyde during drying was decreased.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.05a
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• pp.162-163
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• 2001

기질농도, HRT, 온도, pH, $Ca^{2+}$ 농도변화에 따른 반응기의 생물막형성과 세포외고분자물질의 조성변화에 따른 기질 제거율을 살펴보았다. 그 결과 반응기의 초기 생물막 형성은 각 조건에 따라서 약간의 차이를 보였다. 반응기 운전 초기에 균에 의해 생산된 세포외고분자물질은 점액질의 형태로 세포벽에 부착되어 주위환경의 해로운 요인으로부터 세포를 보호하는 기능을 가지고 있어 생물막 형성을 촉진시키는 역할을 하였으나, 생물막이 안정화된 후에는 오히려 생물막의 산소투과와 영양분의 접촉을 떨어뜨리는 역할을 하여 기질 제거율을 저하시키는 작용을 하는 것으로 나타났다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.458-465
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• 2011

Response surface methodology (RSM) was applied to optimize substrate conditions of ribose and hydrolyzed wheat gluten solution for Maillard reaction. Independent variables were NaCl concentration of hydrolyzed wheat gluten ($X_1$), concentration of ribose ($X_2$) and concentration of hydrolyzed wheat gluten ($X_3$), while the dependent variables of the central composite design (CCD) were browning index (absorbance 420 nm), DPPH radical scavenging activity (DF) and sensory preference (score). Optimum substrate conditions at $140^{\circ}C$, 30 min reaction were 3% NaCl concentration of hydrolyzed wheat gluten, 6.2% concentration of ribose and 13.27% concentration of hydrolyzed wheat gluten. The coefficients of determination ($R^2$) were 0.975, 0.960 and 0.854, the model fit was very significant (p<0.001). DPPH radical scavenging activities and sensory preferences were predicted as 700 (DF) and 8.42 (score), respectively. The model solution increased more browning and DPPH radical scavenging activities with increasing ribose and hydrolyzed wheat gluten concentration. Especially hydrolyzed wheat gluten concentration was the most influential factor, while NaCl concentration of hydrolyzed wheat gluten hardly affected the responses. Sensory preference was increased with rising wheat gluten concentration and decreasing NaCl concentration of hydrolyzed wheat gluten.