• Applied Biological Chemistry
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• 제34권1호
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• pp.1-7
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• 1991

해바라기씨 단백질에서 plastein을 합성 이용하기 위해 먼저 해바라기씨를 pepsin을 이용해 가수분해하는 최적 조건과, plastein을 합성하는 최적 조건을 구하였다. 최적 가수분해 조건은 pH 1.5, $45^{\circ}C$, 2% 기질농도와 2% pepsin 농도에서 24시간 반응시키는 것이었고 plastein 합성의 최적조건은 기질농도 50%, pH 4.5, $50^{\circ}C$, 0.25% pepsin 농도에서 18시간 반응시키는 것이었다. Plastein의 생성을 확인하기 위해 thin layer chromatography를 실시한 결과 해바라기씨 농축가수분해물의 TLC pattern과 plastein의 TLC pattern이 하나의 spot를 제외하고는 다르게 나타났는데 이는 plastein과 기질이 다른 것임을 표시하는 것이었다.

• 상하수도학회지
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• 제24권1호
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• pp.15-24
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• 2010

Coagulation can be used for pretreatment of NF membrane filtration. Foulants such as organic matter and particulate can be removed effectively with the process while high flux recovery is maintained. Recently various types of polyaluminium coagulants including polyaluminium chloride(PAC) are commercially available for water treatment. This study examines effects of polymeric Al and hydrolysis products of PAC on nanofiltration membrane performance. Dominant hydrolysis products were polymeric Al, $Al(OH)_3$, and ${Al(OH)_4}^{-1}$ at acidic, neutral, and alkaline pH conditions, respectively. Under acidic pH condition, flux decline was increased with increasing PAC concentrations, possibly due to polymeric Al adsorption on membrane pore and/or surfaces. For neutral and alkaline pH conditions, little flux decline was observed with increasing PAC concentrations except the highest ${Al(OH)_4}^{-1}$ concentration, with which rapid flux decline was shown. Removal of ionic matters was also varied with pH conditions in this study. Especially, conductivity removal was substantially low and $Ca^{2+}$ concentration in the permeate was quite high at neutral pH condition.

• 한국토양비료학회지
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• 제44권1호
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• pp.48-52
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• 2011

The effect of soil water content on the transformation potential of N compounds derived from hydrolysis of urea applied in a reclaimed tidal soils which was saline-sodic was observed to evaluate nitrification rates of urea. Soil samples were collected from Moonpo series at the newly reclaimed area in Saemanguem. For the transformation potential of N compounds from urea (46% N), newly reclaimed tidal soils (RS) were amended with urea at the rates of 0, 10, and 20 kg $10a^{-1}$. With leachate obtained from the incubated RS in a leaching tube at $25^{\circ}C$, urea hydrolysis and nitrification were measured for a total of 30days. The cumulative amounts of $NO_3{^-}$-N in each of the four soils treated with urea was linear with time of incubation. Results showed that increase in pH occurred with increasing application rate of urea and volumetric water content due to hydrolysis of urea. The total N in the RS was decreased with incubation time, indicating that rates of urea hydrolysis was influenced by soil moisture conditions. Also, the cumulative amount of nitrate in RS gradually increased with increase in time of incubation.

• KSBB Journal
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• 제4권2호
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• pp.78-86
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• 1989

에너지소모를 최소화하고 최대의 당화효과를 얻을 수 있는 고효율 당화장치의 개발을 목표로 impeller교반형 bioattritor를 설계, 제작하여 불용성 섬유소를 기질로 실험하였다. Bioattrotor의 효용성과 효소당화촉진 mechan-ism을 규명하였으며, 최적운전조건을 검토하였다. 분쇄 마찰매체함유 반응기에 일정한 탄성계수를 지닌 spiral spring coil을 내장한 torzue측정장치를 개발, 부하되는 torque, power, 그리고 소요에너지를 측정하여 이를 당화촉진과 비교함으로서 bioattritor의 경제성을 검토하였다. 분쇄마찰매체의 첨가량 및 종류, impeller형태, 교반속도는 중요한 요소로서 작용하였다. 비록 더 연구가 필요하나 분쇄마찰매체의 교반에 소모되는 동력은 당화 촉진효과의 증대에 따른 당화시간의 단축과 섬유소의 고효율 전환에 따른 고농도당의 확보등에 의해 보상되리라 예상된다.

• Journal of Microbiology and Biotechnology
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• 제2권3호
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• pp.197-203
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• 1992

Studies of the pretreatment of chitin and its subsequent hydrolysis by Aspergillus carneus chitinase are reported. Ball milling was found to be the most effective way among the pretreatment methods tested. Data are presented describing the effect of enzyme and substrate concentrations on the rate and extent of the hydrolysis process. It was found that the successive addition of enzyme improved the saccharification yield. Significant product inhibition of the chitinase was observed when N-acetylglucosamine concentration was 3.6％ or higher. Adsorption of enzymes to the substrate occurred during a 24 hr hydrolysis period. An initial rapid and extensive adsorption occurred, followed by gradual desorption which increased during the time of reaction. Intermediate removal of the hydrolyzate and continuation of the hydrolysis by adsorbed enzyme on the residual chitin was also investigated. A total of 75.4 g/l reducing sugars, corresponding to 69.2％ saccharificaton yield (as N-acetylglucosamine) was obtained. In addition an increase in the amount of recoverable enzymes was observed under these conditions. Evidence presented here suggests that the technique, whereby the free enzymes in the recovered hydrolyzate are re-adsorbed onto the new substrate, may provide a means of recirculating the dissolved enzymes.

• 한국식품과학회지
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• 제41권6호
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• pp.622-627
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• 2009

홍게 가공부산물을 고부가가치 식품소재로 이용하기 위하여 단백질 분해효소를 이용하여 가수분해하고 반응표면분석법으로 가수분해 조건을 최적화 하였다. 홍게 가공부산물을 단백질 분해 효소인 Flavourzyme으로 가수분해한 결과 효소반응곡선은 반응 초기 빠른 반응속도를 나타내다가 이 후에 느려지는 전형적인 형태를 나타내었다. 반응초기 90분까지 가수분해도는 30%까지 증가하다가, 이후 최종적으로 32-36%를 나타내었다. 최적화를 하기 위한 가수분해 요인변수로는 반응온도, 반응시간 및 홍게 가공부산물에 대한 Flavourzyme의 양을 선정하였고, 5개의 수준에서 부호화하여 이들을 중심합성설계법을 이용하여 반응표면분석을 실시하였다. 홍게 가공부산물을 Flavourzyme을 이용하여 반응표면 분석법으로 가수분해 조건을 최적화한 결과, 온도 $51.8^{\circ}C$, 반응시간 4시간 45분, 홍게 가공부산물에 대한 Flavourzyme의 양 3.8%로 나타났다. 홍게 가공부산물 효소분해물은 향미소재 및 반응향 제조의 전구물질로서 이용할 수 있을 것이다.

• 한국염색가공학회지
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• 제6권2호
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• pp.10-16
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• 1994

Neutral salts have negative or positive effects on the rates of many chemical reactions and also on the rates of acidic and alkaline hydrolysis of carboxylic esters. The direction of neutral salt effects on the hydrolysis of ester depends on the charge of esters. Neutral salts accelerate alkaline hydrolysis of esters with negative charge, but decelerate alkaline hydrolysis of esters with positive charge, and have little effect on the alkaline hydrolysis of neutral esters. It is expected that the rate of the alkaline hydrolysis of Poly(ethylene terephthalte) (PET), polymeric solid carboxylic polyester with carboxyl end group at the polymer end, is also influenced positively by neutral salts. In the present work, to clarify the mechanism of the neutral salt effect on the alkaline hydrolysis of PET, many salts with different anions like NaF, NACl, NaBr, NaI were added to the aqueous alkaline solutions. Then PET was hydrolyzed with aqueous solutions of many salts in alkali metal hydroxides under various conditions. Some conclusions obtained from the experimental results were summarized as follows. The reaction rate of the alkaline hydrolysis of PET was increased by the addition of neutral salts and In k was increased nearly linearly with the square root of ionic strength of reaction medium. This fact suggested that the ionic strength effect by Debye-Huckel and Bronsted theory was exerted on the reaction. The specific salt effect was also observed. The reaction rate was increased with the decrease in the nucleophilicity of anions of neutral salts, i.e., in the order of $F^-$ <$Cl^-$<$Br^-$<$I^-$. It was thought that the reaction rate was increased in the order of $F^-$ <$Cl^-$<$Br^-$<$I^-$. because the completion of anions with $OH^-$ for carbonyl carbon became weaker with the decrease in the nucleophilicity and with the increase in the size of anions.

• 한국염색가공학회지
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• 제29권4호
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• pp.181-194
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• 2017

The biodegradability of polylactic acid(PLA) fabrics was evaluated by two methods: enzyme and soil degradation. Three different enzymes were selected to evaluate. Degradation times were measured at optimal enzyme treatment conditions. Biodegradation by enzymatic hydrolysis was compared with soil degradation. As a result, biodegradation created cracks on the fiber surface, which led to fiber thickening and shortening. In addition, new peak was observed at $18.5^{\circ}$ by degradation. Moreover, cracks indicating biofragmentation were confirmed by enzyme and soil degradation. By enzyme and soil degradation, the weight loss of PLA fabrics was occurred, there through, the tensile strength decreased about 25% by enzyme hydrolysis when 21 days after, and 21.67% by soil degradation when 60 days after. Furthermore, the biodegradability of PLA fabrics by enzymatic and soil degradation was investigated and enzymatic degradation was found to be superior to soil degradation of PLA fabrics. Among the three enzymes evaluated for enzymatic degradation, alcalase was the most efficient enzymes. This study established the mechanism of biodegradation of PLA nonwovens, which might prove useful in the textile industry.

• 한국염색가공학회지
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• 제8권4호
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• pp.25-30
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• 1996

This study was carried out to examine the effect of lipase on the removal of tripalmitin in the various conditions of washing. The relations between the removal and the hydrolysis of tripalmitin by lipase were discussed. The hydrolysis characteristics of lipase were examined by a colorimetric determination of liberated fatty acids as a new assay of lipase in reverse micelies. The hydrolysis of tripalmitin by lipase was increased with the increase of reaction time and reaction above lipase concentration 150mg/l pH at reaction temperature 4$0^{\circ}C$.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3665-3676
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• 2023

The use of ion exchange resins to remove ionic impurities from solution is prevalent in industrial process systems, including in the primary heat transport system (PHTS) purification circuit of nuclear power plants. Despite its extensive use in the nuclear industry, our general understanding of ion exchange cannot fully explain the complex chemistry in ion exchange beds, particularly when operated at or near their saturation limit. This work investigates the behaviour of mixed-bed ion exchange resin, saturated with species representative of corrosion products in a CANDU (Canadian Deuterium Uranium) reactor PHTS, particularly with respect to iron chemistry in the resin bed and the removal of lithium ions from solution. Experiments were performed under deaerated conditions, analogous to normal PHTS operation. The results show interesting iron chemistry, suggesting the hydrolysis of cation resin bound ferrous species and the subsequent formation of either a solid hydrolysis product or the soluble, anionic Fe(OH)₃^-.