• Title, Summary, Keyword: hydrolysis

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Overview of Hydrolysis : A Review Part I- Hydrolysis Mechanism

  • Kim, Kwang-Jea
    • Elastomers and Composites
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    • v.55 no.2
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    • pp.128-136
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    • 2020
  • The hydrolysis mechanisms as well as the hydrolysis measurement technique and its practical applications in material manufacturing fields are revised. This chapter, Part 1, elaborates the theoretical aspects of the hydrolysis mechanism. Acid-catalyzed and base-catalyzed hydrolysis mechanisms are reviewed. The quantitative analysis method based on the SIM technique using py-GC-MS is reviewed. Examples of hydrolysis of alkoxysilane in elastomer composites currently used in the industry and hydrolysis of amine in plastic composites are shown. Moreover, Part 2 discusses the mechanical property changes in elastomer and plastic composites after hydrolysis.

Single Hydrolysis Method for the Amino Acid Determination in Foods and Composite Dishes (식품의 아미노산 정량을 위한 단일가수분해 방법의 개발)

  • 박내선
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.3
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    • pp.422-429
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    • 1997
  • For the complete and accurate amino acid determination of protein and food samples, 3 different hydrolysis procedures have been conducted in parallel for each sample, which include the alkaline hydrolysis for tryptophan determination, performic acid oxidation prior to the acid hydrolysis for the determination of cysteine and cystine, and the 6N HCl hydrolysis for the determination of the rest of amino acids. In the present study, amino acid concentrations obtained from the modified single hydrolysis procedure were compared with the values from the conventional hydrolysis procedures in casein and nine food and composite dish samples. In most of the samples tested, the modified single hydrolysis procedure gave significantly higher values of cysteins and cystein compared to the performic acid oxidation method, but resulted in a considerable destruction of tryptophan in food and composited dish samples. There was no consistent difference in the rest of amino acid concentrations between the two hydrolysis systems. Therefore, for complete amino acid determination of various foods and composite dishes, the single hydrolysis method may replace the 6N HCl hydrolysis and performic acid oxidation methods, and thereby reduces 3 hydrolyses to 2 steps with much higher recoveries of the sulfur containing amino acids.

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A Study of Biological Hydrolysis Efficiency for Methane Digestion with Municipal Solid Waste (메탄발효를 위한 도시쓰레기 초고온 가용화 방법의 효율성 검토)

  • Cheon, Ji-Hoon;Hiroshi, Tsuno
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.5
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    • pp.561-572
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    • 2010
  • The efficiency of biological hydrolysis at $80^{\circ}C$ on municipal solid waste mixed with anaerobic digestion sludge was investigated in 100L batch reactors. The hydrolysis effect was observed within a day, when the hydrolysis reactor used for a pre-treatment reactor for methanogenesis, and the effect was observed during two days, When the reactor used for post-treatment reactor. For both configurations, methane production rate decreased, when hydrolysis was carried out more than a day. Gaseous ammonia in the hydrolysis reactors was successtully removed by the ammonia stripping system. Microbial diversity analysis on the hydrolysis reactors indicated dependency of microbial diversity on the configuration of the hydrolysis reactors. Carbohydrate and lactate degrading microbes dominated in the hydrolysis reactor, when the hydrolysis reactor used for a pre-treatment reactor for methanogenesis, while protein degrading microbes dominated in the post-treatment reactor.

Microwave-assisted Weak Acid Hydrolysis of Proteins

  • Seo, Mi-Yeong;Kim, Jin-Hee;Park, Se-Hwan;Lee, Ji-Hye;Kim, Tae-Hee;Lee, Ji-Hyeon;Kim, Jeong-Kwon
    • Mass Spectrometry Letters
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    • v.3 no.2
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    • pp.47-49
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    • 2012
  • Myoglobin was hydrolyzed by microwave-assisted weak acid hydrolysis with 2% formic acid at $37^{\circ}C$, $50^{\circ}C$, and $100^{\circ}C$ for 1 h. The most effective hydrolysis was observed at $100^{\circ}C$. Hydrolysis products were investigated using matrixassisted laser desorption/ionization time-of-flight mass spectrometry. Most cleavages predominantly occurred at the C-termini of aspartyl residues. For comparison, weak acid hydrolysis was also performed in boiling water for 20, 40, 60, and 120 min. A 60- min weak acid hydrolysis in boiling water yielded similar results as a 60-min microwave-assisted weak acid hydrolysis at $100^{\circ}C$. These results strongly suggest that microwave irradiation has no notable enhancement effect on acid hydrolysis of proteins and that temperature is the major factor that determines the effectiveness of weak acid hydrolysis.

Alkaline Hydrolysis Behavior of Poly(trimethylene Terephthalate) Fiber (폴리(트리메틸렌 테레프탈레이트) 섬유의 알카리 가수분해거동)

  • 김영호;이희민;김정철
    • Textile Science and Engineering
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    • v.37 no.2
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    • pp.118-125
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    • 2000
  • Alkaline hydrolysis was carried out on PTMT fibers and the changes in the properties of the hydrolyzed PTMT fiber were investigated. PTMT fibers were hydrolyzed in LiOH, NaOH, and KOH solutions, and the hydrolysis rates of PTMT fibers were in the order of LiOH, NaOH, and KOH. The weight loss increased proportionally with increase in treatment time. In general, the hydrolysis rate of PTMT fiber was lower than PET under the same treatment conditions. Intrinsic viscosity, melting temperature, and density data of the hydrolyzed PTMT fibers indicated that the hydrolysis occurred mainly at the fiber surface. The hydrolysis rate constants of the PTMT fibers were calculated and the hydrolysis activation energy of PTMT fiber obtained from Arrhenius plot was 24 kcal/mol, which was lower than that of PET, 15~19 kcal/mol. Addition of diols such as ethylene glycol and 1,3-propanediol in NaOH solution had little effect on hydrolysis rate, but the presence of n-alcohol increased the hydrolysis rate. The hydrolysis rate was influenced by varying the n-alcohol and its concentrations At 10% (v/v) concentration, the hydrolysis rate increased in the order of methanol, ethanol, n-propanol, and n-butanol. Further increase in the number of carbon did not increase the rate. Thus, the hydrolysis rates of n-hexanol and n-pentanol were even slower than that of n-butanol.

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Overview of Hydrolysis : A Review Part II- Hydrolysis Application

  • Kim, Kwang-Jea
    • Elastomers and Composites
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    • v.55 no.2
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    • pp.137-146
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    • 2020
  • Part 1 provides a theoretical introduction of the hydrolysis mechanism, while Part 2 introduces other types of reaction mechanisms after hydrolysis in elastomer and PA66 composites. We reviewed the condensation reaction, which occurs after hydrolysis in bi-functional alkoxy silane (TESPD & TESPT), and investigated its effects on the mechanical properties of the composites. We also reviewed activators such as zinc soap, which enhances the mechanical properties of silica-silane-filled elastomer composites. The interaction parameter of silica-silane-filled elastomer composites [αC (alpha C)] were also discussed. The effects of hydrolysis on the mechanical property changes in plastic composites were compared and reviewed.

Hydrolysis of the Ester Crosslinking on Cotton Fabric Treated with Polycarboxylic Acid(I) (polycarboxylic acid 처리면포의 Ester 가교결합의 가수분해 (I))

  • 강인숙;배현숙
    • Textile Coloration and Finishing
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    • v.15 no.4
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    • pp.24-31
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    • 2003
  • In this research, we applied FT-IR spectroscopy to study the hydrolysis of the ester-crosslinking formed by various polycarboxylic acids on the cotton fabric. We observed the following; (1) the ester-crosslinking is less durable to hydrolysis than ether-crosslinking under all conditions; (2) the ester-crosslinking formed by polycarboxylic acids having more than three carboxyl groups, such as butanetetracarboxylic acid (BTCA), are substantially more durable to hydrolysis than the acids having two or three carboxyl groups, such as maleic and citric acid; (3) alkaline conditions drastically accelerate the hydrolysis of both urea- and ester-crosslinking; and (4) the ester-crosslinking formed by poly(maleic acid) is more resistant to hydrolysis at alkaline conditions than BTCA. (5) polycarboxylic acid molecules were removed from the fabric at same rate as the hydrolysis of the ester linkage. FT-IR spectroscopy has proved to be a useful analytical technique for evaluating the hydrolysis of the crosslinked cotton fabric.

Angiotensin I Converting Enzyme Inhibitory Activity of Krill (Euphausia superba) Hydrolysate

  • Kim Dong-Soo;Park Douck-Choun;Do Jeong-Ryong
    • Fisheries and aquatic sciences
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    • v.5 no.1
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    • pp.21-27
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    • 2002
  • Angiotensin I converting enzyme inhibitory activities of shelled krill (Euphausia superba) hydrolysates by autolysis and by hydrolysis with commercial proteases were analyzed. Among the proteases, Alcalase was the most effective protease for the hydrolysis of krill considering the degree of hydrolysis $(87.5\%)$ and the ACE inhibitory activity $(60\%)$. Four hour hydrolysis suggested as the most suitable and economic. In order to establish the optimum hydrolysis condition of krill, degree of hydrolysis and ACE inhibitory activity as affected by Alcalase concentration and water amount added were statistically analyzed by response surface methodology (RSM). The optimum hydrolysis condition was $2.0\%$ Alcalase hydrolysis in 2 volumes (v/w) of water at $55\% for 4 hr. The hydrolysate prepared from the optimum hydrolysis condition was fractionated by molecular weight. The lower molecular weight fraction showed the higher ACE inhibitory activity. $IC_{50}$ of the fraction under 500 Da was 0.57mg protein/mL.

Hydrolysis of the Ester Crosslink on Cotton Fabric Treated with Combination of Poly(maleic acid) and Citric Acid (Poly(maleic acid)/Citric Acid 혼합 처리면포의 Ester 가교결합의 가수분해)

  • Kang In-sook;Bae Hyun-sook
    • Textile Coloration and Finishing
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    • v.17 no.3
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    • pp.16-25
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    • 2005
  • In this research, we investigated hydrolysis of the ester crosslinking on cotton fabric treated with polymer of maleic acid(PMA), citric acid(CA) and combination of polymer of maleic acid and citric acid using Fourier transform infrared spectroscophy. The rate of hydrolysis of the ester crosslinkage increased with pH regardless of the type of polycarboxylic acid used and even after hydrolysis for 256 hour in pH 13_4 solution, the treated fabric retained $10-20\%$ ester crosslinkage. The durability to alkaline hydrolysis of the ester crosslinkage formed by CA was lower than that of by PMA and combination of poly(maleic acid) and citric acid indicating that the ester formed by CA on the cotton fabric is more susceptible to hydrolysis than that formed by PMA and combination of PMA and CA. The total amount of ester and polycarboxylic acid molecules removed from fabric increased with increasing hydrolysis time but the rate of hydrolysis of ester linkage were higher than that of removal of polycarboxylic acid molecule from the fabric. The characteristic of hydrolysis of fabric treated with combination of PMA and CA was related with the mixing ratio of PMA and CA in treating fabric.

Autohydrolysis and Enzymatic Saccharification of Lignocellulosic Materials(III) - Recycling and Reutilization of Cellulase Enzyme - (목질 재료의 자기가수분해 및 효소당화에 관한 연구 (Ⅲ) - Cellulase 효소의 회수 및 재사용 -)

  • Cho, Nam-Seok
    • Journal of the Korean Wood Science and Technology
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    • v.17 no.3
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    • pp.45-51
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    • 1989
  • A major problem in the enzymatic hydrolysis of lignocellulosic substrates is the very strong bonding of cellulase to lignin and even cellulose in the hydrolysis residues. This phenomenon inhibits recycle of the cellulase which is a major expense of the enzymatic hydrolysis process. In this paper, autohydrolyzed wood was delignified by two-stage with a 0.3% Na OH extraction and oxygen-alkali bleaching and was subjected to enzymatic hydrolysis with cellulase. Also, an improved almost quantitative recycle process of cellulase enzyme was discussed. In enzyme recovery by affinity method. the first recycling showed relatively high hydrolysis rate of 97.4%. Even at the third recycle. hydrolysis rate was 86.7 percents. In the case of cellulase recovery by ultrafiltration method, first 2 recycling treatments resulted very high hydrolysis rate(97.0-97.7%). Even the third recycling showed about 94.2%. Authoydrolysis of oak wood followed by 2-stage delignification with alkali and oxygen-alkali produced a substrate for enzymatic hydrolysis that allowed almost quantitative recycle of cellulase.

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