• Journal of Pharmaceutical Investigation
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• 제21권4호
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• pp.231-236
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• 1991

The molecular nature of aspirin hydrolysis was studied using cyclodextrin as a biomimetic model for esterase. Cyclodextrin was selected for this purpose because it meets the necessary requirements for the hydrolysis study, Dissociation constants and catalytic rates were obtained under alkaline conditions by the kinetic method.

• 한국축산식품학회지
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• 제27권3호
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• pp.329-336
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• 2007

This study was designed to find the optimum conditions for converting isoflavone glycoside to aglycone by ${\beta}-galactosidase$. Three different forms of the enzyme were tested and the optimum enzyme concentration, incubation temperature, pH, and incubation time were determined. Before treatment with enzyme, isoflavone contained 89.4% glycoside including daidzin, glycitin and genistin, and only 10.6% aglycone including daidzein, glycitein and genistein. Among the enzymes tested, the highest rate of isoflavone hydrolysis to aglycone, 35%, was observed when 3 unit/g Fungal Lactase (Amano Enzyme) was used. Higher incubation temperatures resulted in a higher rate of hydrolysis along with a greater loss of isoflavone mass. Therefore, body temperature $(37^{\circ}C)$ may be adequate for isoflavone conversion, with 44.9% hydrolysis and less than 10% loss of mass. As expected, a higher amount of aglycone was produced at pH 7 compared with other pH values. During 5hr of incubation, the conversion of glycoside to aglycone increased dramatically from 0 to 1hr, and plateaued thereafter. In addition, commercial soy-based milk was hydrolyzed more effectively with ${\beta}-galactosidase$ when incubated for 5hr. Based on the above results, the optimum conditions for isoflavone hydrolysis by ${\beta}-galactosidase$ were for 3 hr at $37^{\circ}C$, pH 7 with 3 unit/g Fungal Lactase (Amano Lactase), yielding an average total amount of aglycone ranging from 40 to 47%.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.67-70
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• 2008

Biological conversion of biomass into fuels and chemicals requires hydrolysis of the polysaccharide fraction into monomeric sugars. Hydrolysis can be performed enzymatically, and with dilute or concentrate mineral acids. In this study, dilute sulfuric acid used as a catalyst for the hydrolysis of rapeseed straw. The purpose of this study is to optimize the hydrolysis process in a 15ml bomb tube reactor and investigate the effects of the acid concentration, temperature and reaction time on the hemicellulose removal and consequently on the production of sugars (xylose, glucose and arabinose) as well as on the formation of by-products (furfural, 5-hydroxymethylfurfural and acetic acid). Statistical analysis was based on a model composition corresponding to a $3^3$ orthogonal factorial design and employed the response surface methodology (RSM) to optimize the hydrolysis conditions, aiming to attain maximum xylose extraction from hemicellulose of rapeseed straw. The obtained optimum conditions were: acid concentration of 0.77%, temperature of $164^{\circ}C$ with a reaction time of 18min. Under these conditions, 75.94% of the total xylose was removed and the hydrolysate contained 0.65g $L^{-1}$ Glucose, 0.36g $L^{-1}$ Arabinose, 3.59g $L^{-1}$ Xylose, 0.51g $L^{-1}$ Furfural, 1.36g $L^{-1}$ Acetic acid, and 0.08g $L^{-1}$ 5-hydroxymethylfurfural.

• 한국수산과학회지
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• 제44권2호
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• pp.99-103
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• 2011

This study was performed to determine the optimal hydrolysis conditions for the production of a flavoring from the precipitation of snow crab cooker effluent (PSCCE) with commercial proteases. Based on cost-per-enzyme activity and sensory evaluations, Flavourzyme$^{(R)}$ 500 MG plus Protamex$^{(R)}$ (1:1 ratio, w/w) were selected as suitable enzymes. Three independent variables consisting of the substrate concentration (S), enzyme-to-substrate ratio (E/S), and hydrolysis time (T) were examined using response surface methodology (RSM). A model equation obtained from RSM was used to predict the degree of hydrolysis (DH) as follows: % DH = 52.285 - 6.371[S] + 5.469[E/S] + 7.599[T] - $5.818[S]^2$ - $5.633[E/S]^2$ - $6.528[T]^2$ - 3.265[E/S][S] - 5.415[T][S] + 4.315[T][E/S]. From the ridge analysis, the conditions favoring the highest degree of hydrolysis were pH 7.45, $55^{\circ}C$, a S of 21.82%, an E/S of 0.50%, and a T of 3.74 h.

• Macromolecular Research
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• 제11권6호
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• pp.476-480
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• 2003

The rate of hydrolysis of Langmuir monolayer films of biodegradable polylactide (PLA) derivates was investigated at the air/water interface. The present study investigated such parameters as surface pressure, pH, and time. The hydrolysis of polyester monolayers depended strongly on the subphase pH, the concentration of active ions. Under the conditions studied here, polymer monolayers showed faster rates of hydrolysis when they were exposed to a basic subphase rather than they did when exposed to acidic or neutral subphases. By increasing the concentration of the degradation medium, the hydrolytic rate of dl-PLA monolayers was accelerated (accelerating effect). In addition, the basic hydrolysis of modified PLA with small amounts of hydrophilic (benzyloxycarbonyl) methyl morpholine-2,5-dione or glycolide was much faster than that of the PLA homopolymer.

• 한국군사과학기술학회지
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• 제10권1호
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• pp.116-122
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• 2007

A 2-step process for the safe disposal of chemical warfare agents(agent hydrolysis followed by incineration In the submerged-quench incinerator) was studied to obtain basic data for the design of pilot plant in the future. Sample materials used for the hydrolysis reaction were sarin(GB), sulfur mustard (HD), and methylphosphonic difluoride(DF). The hydrolysates of these materials were thermally destroyed in a submerged-quench incineration system. Experimental conditions for achieving destruction efficiency of 99.99% in both steps were established and phosphoric acid was recovered from the waste water when destroying DF hydrolysate in the incinerator. Treated water could be reused as process water for the agent hydrolysis.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권5호
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• pp.291-293
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• 2003

Batch reactors were employed to investigate the kinetics of cellulose hydrolysis under extremely low acid (ELA) and high temperature condition. The sawdust was pretreated by Auto-hydrolysis prior to the batch reaction. The maximum yield of glucose obtained from the batch reactor experiment was about 70% for the pretreated sawdust, this occurred at 210 and 22$0^{\circ}C$. The maximum glucose yield from the untreated sawdust was much lower at these temperatures, about 55%. The maximum yields of glucose from the lignocellulosics were obtained between 15th and 20th minutes after which gradual decrease was observed.

• 생명과학회지
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• 제12권6호
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• pp.765-768
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• 2002

Rhodotorula sp. CL-82 유래 의 epoxide hydrolase 활성을 이용하여 라세믹 styrene oxide에 대한 입체선택적 가수분해 반응을 실시하였다. Rhodotorula sp. CL-82 생촉매의 입체선택적 가수분해속도를 나타내주는 반응표면 곡선에 대한 분석을 통해 pH, 반응주도, cosolvent 첨가량에 대한 최적조건을 각각 7.6,$33.3^{\circ}C$ , 3%(v/v)으로 결정하였다. 최적반응조건에서 약 4시간 정도의 반응을 통해 ee값이 99% 이상인 광학적으로 순수한 (S)-styrene oxide를 이론 수율대비 40% 수율로 얻을 수 있었다.

• 한국식품영양학회지
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• 제8권4호
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• pp.335-343
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• 1995

In order to enhance the utility of alaska-pollack, the optimum conditions for the preparation of pronase hydrolysate. The optimum temperature and pH for the hydrolysis of alaska-pollack by pronase were 4$0^{\circ}C$ and pH 7.0. The reaction time and enzyme concentration were 4 hr and 1,000 units per g of substrate. Under the above optimum conditions alaska-pollack was hydrolysed by pronase yielding a hydrolytic degree of about 89eye. The bitterness and hyrophobicity of pronase hydrolysate were decreased with increasing reaction time. Hydrophobic amino acids(Tyr, Met, Ala, flu, Leu, and Phe) were increased for 2 hr, but fur thor hydrolysis was showed decrease of hydrophobic amino acids content. Palatable amino acids (Asp, Glu, Pro, Ser, Thr and Gly) were increased with hydrolysis time.

• 한국식품영양과학회지
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• 제27권6호
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• pp.1110-1116
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• 1998

To determine the optimum conditions for the enzymic hydrolysis against wheat gluten of high con centrations (6~14%, w/w, protein), a hydrolysis system combining weak acid pretreatment and enzymic hydrolysis was investigated. Alcalase showed the highest DH(degree of hydrolysis) of the tested proteases. After hydrolysis by alcalase, subsequently peptidases were applied for the better DH of the wheat gluten hydrolyzate. Peptidase NP2 showed the highest DH of the tested peptidases, but flavour zyme was shown for the lowest bitter taste of the resulting hydrolyzate. In order to minimize aggregation or gelling at higher initial substrate concentration during heat treatment, wheat gluten suspension was pretreated with possibly low concentrations of hydrochloric acid at 105oC for 1 hour, and then enzy matically hydrolysed with alcalase and subsequently with flavourzyme. Each required minimum concen tration of hydrochloric acid in the wheat gluten suspension of 6, 8, 10, 12, and 14%(w/w, protein) was 0.10, 0.15, 0.20, 0.225, and 0.275N, respectively. After the subsequent enzymic treatment by alcalase and peptidase NP2 for 24 hrs, the nitrogen solubility in the final wheat gluten hydrolysates was increased to 94.9, 86.4, 85.3, 89.3 and 95.0%, and their amino nitrogen content was increased to 2.87, 5.68, 7.34, 9.71 and 12.50mg/m, respectively.