• Journal of Korea Foresty Energy
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• v.18 no.1
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• pp.17-24
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• 1999

This study was conducted to examine the change in the structure of the lignin during liquefaction of kraft pulp lignin in Pinus korainsis and lignin sulfonic acid. The lignin liquefied compounds were extracted with chloroform from aqueous, liquefied lignins. Through the examination by IR, H($^{13}$C) - NMR and GC-MS spectrometers, phenolic compounds such as diguaiacol, acetic acid phenyl ester, phenol, 1-phenyl ethanone were identified with many of unknown phenolic compounds.

• Journal of the Korean Wood Science and Technology
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• v.12 no.3
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• pp.35-40
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• 1984

The ultraviolet absorption spectra of AcBr lignin (Acetyl Bromide lignin) from 10 species grown in Mt. Jiri were determined. There were 3 peak positions, at 249nm (max peak), at 267-268 nm (shallow min. peak) and at 280 nm (lower max. peak). The Bjorkman lignin and lignin sulfonic acid spectra had shoulders, but the AcBr lignin had not them. Average absorbances and absorptivities of the AcBr lignins at peak positions were $0.367{\pm}0.0015$, $24.56{\pm}0.0535$, at 249 nm, $0.278{\pm}0.0016$, $18.50{\pm}0.0569$, at 267-268 nm and $0.306{\pm}0.0016$, $20.42{\pm}0.0627$ at 280 nm, respectively.

• Journal of the Korean Wood Science and Technology
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• v.25 no.2
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• pp.21-26
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• 1997

Lignin viscous material was prepared from acetosolve lignin by phenolation and heat treatment. The yield of phenolation was about 160% with p-toluene sulfonic acid(2% of acetosolve lignin) as catalyzer. Phenolated lignin has a good spinnability and thermosetting property by $300^{\circ}C$ treatment with vaccum. Acetosolve lignin carbon fiber has $20{\pm}5$ m diameter and $68.2{\pm}10\;kg/mm^2$ tensile strength. The yield of carbon fiber based on acetosolve lignin was 31%.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.5 s.118
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• pp.1-8
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• 2006

This study was performed to evaluate extensive electrochemical characteristics of 23 commercially available mediators for laccase. Electrochemical properties, interactions with laccases, and ability to degrade lignin were compared for selected mediators. Among them, NNDS has very similar electrochemical properties in terms of reversibility and redox potential (about 470 mV vs. Ag/AgCl at pH=7) compared to ABTS which is a well-known mediator. Specific activity of purified laccase from Cerrena unicolor was determined by both 2,2'-azino-bis-(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS) and 1-nitroso-2-naphthol -3,6-disulfonic acid (NNDS). The specific activity of the laccase was 23.2 units/mg with ABTS and 21.2 units/mg with NNDS. The electron exchange rate for NNDS with laccase was very similar to that for ABTS, which meant that NNDS had similar mediating capability to ABTS. Determining methanol concentration after reacting with laccase compared to lignin degradation capabilities of both ARTS and NNDS. ARTS or NNDS alone cannot degrade lignin, but in the presence of laccase enhanced the rate of lignin degradation. ABTS showed better activity in the beginning, and the reaction rate of NNDS with lignin was about a half of that of ABTS at 10 minute, but the final concentration of methanol produced in 1 hour was very similar each other. The reason for similar methanol concentration for both ABTS and NNDS can be interpreted as the initial activity of ABTS was better than that of NNDS, but ABTS would be inhibited laccase activity more during the incubation.

• Journal of the Korean Wood Science and Technology
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• v.22 no.2
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• pp.54-60
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• 1994

The pine bark from mechanical pulp industry was cooked with bisulfite liquor, and the chemical and physical properties of the spent liquor after cooking for 90 minutes, which allowed partial defibration were determined. Lignosulfonate or lignin-related materials in the spent liquor have a molecular weight of approximately 3,000, which is lower than that of commercial lignosulfonate (C-LS) prepared from wood. The sulfonic equivalent weight calculated by colloid titration was 307 for C-LS, 238~239 for spent liquor. The contents of lignosulfonic acid and phenolic hydroxyl groups on $C_9$ unit of lignin in the spent liquor were 0.98~0.99, and 1.51~1.66, respectively. These values were remarkably higher than those of C-LS. Especially the content of phenolic hydroxyl group was almost twice that of C-LS. The viscosity of spent liquor after freeze drying was very low compared to C-LS. The dispersing ability of spent liquor was almost equivalent to or more than that of C-LS.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.291-294
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• 2006

Studies of the effectiveness of anthraquinone (AQ) in kraft-AQ pulping in terms of its mechanism of mass transfer have been conducted. Experiments performed have demonstrated an 'apparent solubility' of AQ in caustic solutions of wood lignin. The adsorption behavior of AQ species was also analyzed. Anthraquinone-2-sulfonic acid (AQ-S), a water-soluble derivative of AQ, showed selective adsorption on wood. A mechanism for the transport of AQ into wood chips during kraft pulping are proposed, and some explanations for previously unexplained observations are addressed.

• Journal of the Korean Wood Science and Technology
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• v.14 no.4
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• pp.14-20
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• 1986

These experiments were carried out to determine the ultraviolet absorption spectra of AcBr lignins(acetyl bromide lignin) from 10 hardwood species grown in Mt. Jiri. 1. There were 3 peak positions, at 249nm(max. peak), at 262-266nm(shallow min. peak) and at 270-280nm(lower max. peak). The Bj$\ddot{o}$rkman lignin and lignin sulfonatic acid spectra had shoulders, but the AcBr lignin didn't. 2. Average absorbances of the AcBr lignin at peak positions were 0.457${\pm}$0.0077 at 249nm, 0.297${\pm}$0.0029 at 262-266nm and 0.309${\pm}$0.0067 at 270-280nm. 3. Average absorptivities of the AcBr lignin at peak positions were 25.005${\pm}$0.3825 at 249nm, 16.264${\pm}$0.2347 at 262-266nm and 16.863${\pm}$0.3444 at 270-280nm. 4. AcBr lignin absorptivities in each species were as follows: 16.939${\pm}$0.3735 in Acer pseudo-sieboldianum var. koreanum, 17.411${\pm}$0.2937 in Carpinus laxiflora, 16.579${\pm}$0.4348 in Comus controversa, 16.385${\pm}$0.4140 in Fraxinus rhynchophylla, 16.287${\pm}$0.4156 in Meliosma myriantha, 16.492${\pm}$0.1432 in Platycarya strobilacea, 16.343${\pm}$0.3177 in Prunus sargentii, 17.549${\pm}$0.3253 in Sophora japanica, 18.400${\pm}$0.2925 in Stewartia koreana, 16.245${\pm}$0.4339 in Styrax obassia. 5. As the spectra of AcBr lignin from hardwood showed the unpromounced peak from 270nm to 280nm, it was supposed that thes hardwood lignins were the guaiacyl-syringyl copolymers.

• KSBB Journal
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• v.16 no.2
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• pp.179-182
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• 2001

The use of 2,2-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)(ABTS) as a radical mediator enhanced the bleaching efficiency of kraft pulp by horseradish peroxidase(HRP) and $H_2O_2$. High concentrations of up to 20 mM $H_2O_2$. were used. The bleaching of the kraft pulp increased as the amount of HRP and ABTS concentration were inceased up to 0.3 mg/90 mL and 2 mM, respectively. The bleaching of the kraft pulp was closely related with the HRPs activity and its adsorption onto the pulp. The activity of HRP and bleaching of kraft pulp were maximum at pH 7 and were reduced either in a acidic or alkaline solutions. The adsorption of HRP onto pulp was low in solutions of pH 6-8 and high in an acidic(pH5) and an alkaline solutions(pH 9). The adsorption of the enzyme was greater for alkali-lignin than for crystalline cellulose, the two major components of pulp.

• The Korean Journal of Mycology
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• v.32 no.2
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• pp.112-118
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• 2004

Laccase produced by Trametes hirsuta S1 isolated from Korea was partially purified and characterized using ultrafiltration, anion exchange chromatography and affinity chromatography. The laccase was produced as the predominant extracellular enzyme during primary metabolism. Neither lignin peroxidase nor veratryl alcohol oxidase (VAO) were detected in the culture fluid. Addition of 2,5-xylidine enhanced 4-fold laccase production. Purified laccase was a single polypeptide having a molecular mass of approximately 66 kDa, as determined by SDS-polyacrylamide gel electrophoresis, and carbohydrate content of 12%. $K_{m}\;and\;V_{max}$ values for laccase with ABTS [2,2-azinobis (3-ethylbenzthiazoline 6-sulfonic acid)] as a substrate (Lineweaver-Burk plot) was determined to $51.2\;{\mu}M\;and\;56.8\;{\mu}mole$, respectively. The optimal pH for laccase activity was found to be 3.0. The enzyme was very stable for 1 hour at $50^{\circ}C$. Half-life ($t_{1/2}$) of the enzyme was about 20 min at $70^{\circ}C$. Spectroscopic analysis of purified enzyme indicated that the enzyme was typical of copper-containing protein. Substrate specificity and inhibitor studies for laccase also indicated to be a typical fungal laccase. The N-terminal amino acid sequence of the T. hirsuta S1 laccase showed 100% of homology to those of laccase from C. hirsutus.

• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1069-1076
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• 2010

A novel laccase from Tricholoma mongolicum was purified by using a procedure that entailed ion-exchange chromatographies on DEAE-cellulose, CM-cellulose, and Q-Sepharose, and FPLC-gel filtration on Superdex 75. The purified enzyme was obtained with a specific activity of 1,480 U/mg-protein and a final yield of 15%. It was found to be a monomeric protein with a molecular mass of 66 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its N-terminal amino acid sequence was GIGPVADLYVGNRIL, similar to some but also different to other mushroom laccases. The optimum pH and temperature for the purified enzyme were pH 2 to pH 3 and $30^{\circ}C$, respectively. It displayed a low $K_m$ toward 2,7-azinobis (3-ethylbenzothiazolone-6-sulfonic acid) diammonium salt (ABTS) and high $k_{cat}/K_m$ values. The purified laccase oxidized a wide range of lignin-related phenols, but exerted maximal activity on ABTS. It was significantly inhibited by $Hg^{2+}$ ions, and remarkably stimulated by $Cu^{2+}$ ions. It inhibited HIV-1 reverse transcriptase and proliferation of hepatoma HepG2 cells and breast cancer MCF7 cells with an $IC_{50}$ of 0.65 ${\mu}M$, 1.4 ${\mu}M$, and 4.2 ${\mu}M$, respectively, indicating that it is also an antipathogenic protein.