• Title, Summary, Keyword: Cellulose Hydrolysis

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Cellulose Hydrolysis by Digestive Enzymes of Reticulitermes speratus, a Native Termite from Korea

  • Lee, Young-Min;Kim, Hyun-Jung;Cho, Moon-Jung;Shin, Keum;Kim, Young-Kyoon;Kim, Yeong-Suk
    • Journal of the Korean Wood Science and Technology
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    • v.38 no.2
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    • pp.140-148
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    • 2010
  • This study was to investigate the enzymatic hydrolysis of cellulose using the cellulase from whole body of the native termite collected in Milyang-si, Kyungsangnamdo, Korea. In the results, optimal temperature and pH for the enzyme of native termites were $45^{\circ}C$ and pH 5.5 for both endo-${\beta}$-1, 4-glucanase and ${\beta}$-glucosidase. Enzyme activity of the termite enzyme was shown $8.8{\times}10^{-2}\;FPU/m{\ell}$. And the highest glucose hydrolysis rate of cellulose by the digestive enzyme from test termites was 24.5% based on the glucan, comparing 59.7% by commercial enzyme (only celluclast 1.5 L) at 1% (w/v) substrate and 36 hours in hydrolysis time. This hydrolysis rate by the digestive enzyme from test termites was comparatively high value in 41% level of the commercial enzyme. When cellulose was hydrolyzed by the digestive enzyme of the native termite, glucose hydrolysis was almost completed in 12 hours which was the considerably reduced time for cellulose hydrolysis. It was suggested that the quiet short reaction time for cellulose hydrolysis by the enzyme from native termite could be a very high advantage for development of hydrolysis cellulase for lignocellulosic biomass.

Kinetic Studies on Enzymatic Hydrolysis of Cellulose(I) -Effect of Structural Features of Cellulose on Enzyme Adsorption- (섬유소 가수분해반응에 관한 연구(I) -효소흡착에 대한 섬유소의 구조적 특성-)

  • Lee, Yong-Hun;Kim, Chul
    • KSBB Journal
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    • v.6 no.2
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    • pp.157-166
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    • 1991
  • The structural properties of cellulose are significantly changed with the progress of hydrolysis reaction. The effects of changes on such properties of cellulosic substrate as crystallinity, amicessibility of enzyme to the active site of cellulose surface, and particle size on the kinetics of enzymatic hydrolysis have been studied. Among those physical studies, the apparent surface active site of cellulose particle was found to have the most significant effect on the hydrolysis kinetics. Based on the experimental results, the adsorption affinity of enzyme and hydrolysis rate were mainly influenced by the surface roughness of cellulose particle. The extent of accesssible active site may be expressed as the change of particle diameter. The Langmuir isotherm was proposed in terms of enzyme activity to explain the actual action of enzyme protein.

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Effect of a Nonionic Surfactant on the Adsorption and Kinetic Mechanism for the Hydrolysis of Microcrystalline Cellulose by Endoglucanase Ⅰ and Exoglucanase II

  • 김동원;장영훈;정영규;손기향
    • Bulletin of the Korean Chemical Society
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    • v.18 no.3
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    • pp.300-305
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    • 1997
  • Effect of a nonionic surfactant, Tween 20 on the adsorption and kinetic mechanism for the hydrolysis of a microcrystalline cellulose, Avicel PH 101, by endoglucanase Ⅰ (Endo Ⅰ) and exoglucanase Ⅱ (Exo Ⅱ) isolated from Trichoderma viride were studied. The Langmuir isotherm parameters, amount of maximum adsorption (Amax) and adsorption equilibrium constant (Kad) for the adsorption, were obtained in the presence and the absence of nonionic surfactant. On the addition of Tween 20, the Kad and Amax values of Exo Ⅱ were decreased, while those of Endo Ⅰ were not affected. These indicate that the adsorption affinity of Exo Ⅱ on the cellulose is weakened by nonionic surfactant, and the surfactant enhanced desorption of Exo Ⅱ from insoluble substrate. The enzymatic hydrolysis of the cellulose can be described by two parallel pseudo-first order reactions using the percentages of easily (Ca) and hardly (Cb) hydrolyzable cellulose in Avicel PH 101 and associated rate constants (ka and kb). The Ca value was increased by adding Tween 20 for all enzyme samples (Exo Ⅱ, Endo Ⅰ and their 1:1 mixture) implying that the low-ordered crystalline fraction in the cellulose may be partly dispersed by surfactant. The ka value was not affect by adding Tween 20 for all enzyme samples (Exo Ⅱ, Endo Ⅰ and their 1:1 mixture). The kb value of Exo Ⅱ was increased by adding Tween 20, while that of Endo Ⅰ was not affected. This suggests that the surfactant helps the Exo Ⅱ desorb from microcrystalline cellulose, and increase the hydrolysis rate. These results were show that the increase of hydrolysis of cellulose by the nonionic surfactant is due to both the activation of Exo Ⅱ and partial defibrillation of the cellulose.

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Substitution Characteristics of Carboxymethyl cellulose made from Hydrocellulose (수화(水化) 셀룰로오스로 제조(製造)한 카르복시메틸 세룰로오스의 치환(置換) 특성(特性))

  • Choi, Won-Sil;Ahn, Won-Yung
    • Journal of the Korean Wood Science and Technology
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    • v.20 no.2
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    • pp.81-90
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    • 1992
  • The effect of acid treatment of cellulose on the substitution charateristics of carboxymethylation was studied in this paper. Five samples of hydrocellulose(HC), all prepared from ${\alpha}$-cellulose by hydrolysis with five reaction times and determined on average molecular weight and polydispersity, were carboxymethylated to carboxymethyl cellulose (CMC). The CMCs from HCs were examined upon degree of substitution(DS), distribution of carboxymethyl groups in anhydroglucose units of the cellulose, and unsubstituted anhydroglucose(USAG) content. The DS of CMCs increased with increasing the hydrolysis time except CMC from HC at 1 hour hydrolysis time. In carboxymethylation the availability of hydroxyl groups on anhydroglucose units in HCs was the highest on OH(2), and the relative availability of OH(6) increased with the increasing of the hydrolysis time. The USAG contents were more deviated than that calculated based on Spurlin's model, and had a strong tendency of decreasing with increasing the hydrolysis time. The reactivity of HC was lower than that of ${\alpha}$-cellulose and the relative availability of OH(6) in HC increased with the hydrolysis time.

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Effect of sulfuric acid hydrolysis condition on yield, particle size and surface charge of cellulose nanocrystals (황산 가수분해 조건이 셀룰로오스 나노크리스탈의 수율, 입도 및 전기화학적 특성에 미치는 영향)

  • Ryu, Jae-Ho;Youn, Hye-Jung
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.43 no.4
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    • pp.67-75
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    • 2011
  • Sulfuric acid hydrolysis is a typical approach for producing cellulose nanocrystals. The method has been widely used, but it has a disadvantage of low yield of cellulose nanocrystals compared to mechanical method. To expand the application of cellulose nanocrystals in practical, we should be able to produce them with higher yield and the controlled properties. In this study, therefore, we intended to investigate the effect of sulfuric acid hydrolysis condition on the characteristics of the prepared cellulose nanocrystals. The concentration of sulfuric acid, temperature and hydrolysis time were varied, and the yield as well as diverse properties including the morphology, size and zeta potential were examined. We could obtain cellulose nanocrystals up to 70% of yield and found that the properties were dependent on the reaction condition. It would be helpful to select an appropriate condition for producing cellulose nanocrystals.

Morphology of Nanocelluloses and Micro-sized Cellulose Fibers Isolated by Acid Hydrolysis Method

  • Cho, Mi-Jung;Park, Byung-Dae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.41 no.5
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    • pp.26-32
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    • 2009
  • As a part of utilizing the nanocellulose (NC) from lignocellulosic components of wood biomass, this paper reports preliminary results on the products of sulfuric acid hydrolysis. The purpose of this study was to investigate the morphology of both NC and micro-sized cellulose fiber (MCF) isolated by acid hydrolysis from commercial microcrystalline cellulose (MCC). Field emission.scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were employed to observe the acid hydrolysis suspension, NC, and MCF. The electron microscopy observations showed that the acid hydrolysis suspension, before separation into NC and MCF by centrifugation, was composed of nano-sized NCs and micro-sized MCFs. The morphology of isolated NCs was a whisker form of rod-like NCs. Measurements of individual NCs using TEM indicated dimensions of 6.96$\pm$0.87 nm wide by 178$\pm$55 nm long. Observations of the MCFs showed that most of the MCC particles had de-fibered into relatively long fibers with a diameter of 3-9 ${\mu}m$, depending on the degree of acid hydrolysis. These results suggest that proper technologies are required to effectively realize the potentials of both NCs and MCFs.

Simultanceous Saccharification and Fermentation of Cellulose for Lactic Acid Production

  • Yoon, Hyon-Hee
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.2 no.2
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    • pp.101-104
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    • 1997
  • Lactic acid production from ${\alpha}$-cellulose by simultaneous saccharification and fermentation (SSF) was studied. The cellulose was converted in a batch SSF using cellulase enzyme Cytolase CL to produce glucose sugar and Lactobacillus delbrueckii to ferment the glucose to lactic acid. The effects of temperature, PH, yeast extract loading, and lactic acid inhibition were studied to determine the optimum conditions for the batch processing. Cellulose was converted efficiently to lactic acid, and enzymatic hydrolysis was the rate controlling step in the SSF. The highest conversion rate was obtained at 46$^{\circ}C$ and pH 5.0. The observed yield of lactic acid from ${\alpha}$-cellulose was 0.90 at 72 hours. The optimum pH of the SSF was coincident with that of enzymatic hydrolysis. The optimum temperature of the SSF was chosen as the highest temperature the microoraganism could withstand. The optimum yeast extract loading was found to be 2.5g/L. Lactic acid was observed to be inhibitory to the microorganisms' activity.

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Synthesis and Properties of Superabsorbents from Sodium Cellulose Sulfate-g-PAN(I) - Synthesis of Superabsorbents - (PAN 그라프트 공중함 나트륨 황산 셀룰로오스계 고흡수성 수지의 합성과 성질(I)-고흡수성 수지의 합성-)

  • 송경근;고석원
    • Textile Science and Engineering
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    • v.31 no.9
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    • pp.715-724
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    • 1994
  • To carry out the graft copolymcrization of acrylonitrile(AN) onto a cellulose backbone under homogelleous conditions and to incorporate a strong acitlic group sodium cellulose sulfate(CS) of D.S. 1.14 was synthesized by the reaction or cellulose(MW 166, 000) and 50, -DMF complex. AN was grafted onto CS and the grafting conditions were investigated. Superabsorbent HCSPAH was produced by alkaline hydrolysis of sodium cellulose sulfate-g-PAN (CSPAN). Absorbency, water retention value after centrifuging at 700G. saline absorbency in 0.9% aqueous HaCl solution of HCSPAH and the effect of alkaline hydrolysis conditions on these absorbencies were studied. Optimum alkaline hydrolysis condition was determined from the absorbencies.

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Optimum Conditions of Cellulose-Hydrolysis Reaction with Mixed Enzymes of Cellulase and $\beta$-Glucosidase (셀룰라아제와 베타글루코시다아제의 혼합효소를 사용한 섬유소-가수분해반응의 최적조건)

  • 손민일;김태옥
    • KSBB Journal
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    • v.13 no.1
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    • pp.20-25
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    • 1998
  • Optimum conditions of the cellulose-hydrolysis reaction with mixed enzymes(cellulase extracted from Penicellium funiculosum mixed with $\beta$-glucosidase extracted from Almod) were investigated to increase the production of glucose from cellulose. Experimental result showed that optimum conditions fro pH, activity ratio of $\beta$-glucosidase to cellulase, concentration of mixed enzymes, concentration of cellulose as a substrate, and temperature range were 4.2, 0.4, 0.8, U/mL, 40 g/L, and 37$\pm$3$^\circ C$, respectively. In these conditions, quantities of glucose productions by using mixed enzymes were larger than those by using cellulase at optimum conditions.

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Effect of Metal Ions on the Degradation and Adsorption of Two Cellobiohydrolases on Microcrystalline Cellulose

  • Kim, Dong Won;Jang, Yeong Heon;Kim, Chang Seok;Lee, Nam Su
    • Bulletin of the Korean Chemical Society
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    • v.22 no.7
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    • pp.716-720
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    • 2001
  • To test the metal ion effect, hydrolysis experiments for two cellobiohydrolases (CBHⅠ and CBH Ⅱ) from Trichoderma reesei have been carried out in the presence of 10 mM metal ions, such as Cu++, Mn++, Ca++, Hg++, Ba++, Pb++, and Cd++. The addition of Mn++, Ba++, and Ca++(10 mM) during the hydrolysis of Avicel PH 101 caused an increase in the total reducing sugar (TRS) for CBH Ⅰ by 142, 135, and 114 percent, respectively. Those for CBH Ⅱ increased by 177, 175, and 115 percent, respectively. The Mn++ was the most stimulatory metal ion, whereas Hg++ was the most inhibitory metal ion. The adsorption experiments were performed to investigate how the influence of Mn++ and Hg++ on the hydrolysis is related to the adsorption of cellobiohydrolases on cellulose. The increase in TRS during hydrolysis by adding Mn++ caused an increase in adsorption affinity (Kad) and tightness (ΔHa). While, the decrease of TRS during hydrolysis by adding Hg++ caused a decrease in the adsorption affinity (Kad) and tightness (ΔHa). These results indicate the changes in the tightness and affinity of adsorption by adding metal ions play a crucial role in the degradation of the microcrystalline cellulose.

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