• The Korean Journal of Mycology
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• v.26 no.2 s.85
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• pp.144-152
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• 1998

To obtain white rot fungi which have selective delignification capacity and can be used in biopulping processes, 94 different wood rotting fungi were screened and the capabilities of selected species were evaluated on deciduous and coniferous wood blocks. White rot fungi, first of all, were selected by simple enzyme tests, i.e., cellulase activity test; phenol oxidase activity test; laccase and peroxidase activity test. Most organisms that gave a positive Bavendamm gave a strongly positive laccase test with syringaldazine whereas most of those that gave a negative Bavendamm test also negative test for laccase and peroxidase, even if some exceptions were noted. Wood decay experiement were carried out to select fungal species with selective lignin-degrading ability by inoculating selected fungi to both wood blocks of Populus tomentiglandulosa and Larix leptolepis. After 12 weeks of incubation, weight losses, lignin losses, and morphological characteristics of the decayed wood were investigated. Almost all fungi tested caused 2 or more times of weight losses in P. tomentiglandulosa than in L. leptolepis, while no weight losses were detected from the un-inoculated wood blocks. Ceriporiopsis subvermispora and Phanerochaete chrysosporium were the best delignifiers for both hardwood and softwood. P. chrysosporium, however, was less effective than C. subvermispora. Bjerkandera adusta and two unidentified spp. caused delignification for only P. tomentiglandulosa. B. adusta caused simultaneous rot of all cell wall components, resulted in thinning of the secondary cell wall layers. Other fungi caused selective delignification resulting in the removal of lignin from middle lamella and separation of cells from each other.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.355-363
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• 2015

Asian lignin was efficiently depolymerized with supercritical ethanol and Ru/C catalyst at various reaction temperature (250, 300, and $350^{\circ}C$). Lignin-oil was subjected to several physicochemical analyses such as GC/MS, GPC, and elemental analysis. With increasing reaction temperature, the yield of lignin-oil decreased from 89.5 wt% to 32.1 wt%. The average molecular weight (Mw) and polydispersity index (Mw/Mn) of lignin-oil obtained from $350^{\circ}C$ (547Da, 1.49) dramatically decreased compare to those of original asian lignin (3698Da, 2.68). This is a clear evidence of lignin depolymerization. GC/MS analysis revealed that the yield of monomeric phenols involving guaiacol, 4-ethyl-phenol, 4-methylguaiacol, syringol, and 4-methysyringol increased with increasing reaction temperature, and these were mostly produced with applying hydrogen gas and Ru/C catalyst (76.1 mg/g of lignin). Meanwhile, the carbon content of lignin-oil increased whereas the oxygen content decreased with increasing reaction temperature, suggesting that hydrodeoxygenation was significantly enhanced at higher temperature.

• Journal of Life Science
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• v.31 no.10
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• pp.944-953
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• 2021

Lignin is a complex phenylpropanoid polymer abundant in the cell walls of vascular plants. It is mainly presented in conducting and supporting tissues, assisting in water transport and mechanical strength. Lignification is also utilized as a defense mechanism against pathogen infection or wounding to protect plant tissues. The monolignol precursors of lignin are synthesized by cinnamyl alcohol dehydrogenase (CAD). CAD catalyzes cinnamaldehydes to cinnamyl alcohols, such as p-coumaryl, coniferyl, and sinapyl alcohols. CAD exists as a multigenic family in angiosperms, and CAD isoforms with different functions have been identified in different plant species. Multiple isoforms of CAD genes are differentially expressed during development and upon environmental cues. CAD enzymes having different functions have been found so far, showing that one of its isoforms may be involved in developmental lignification, whereas others may affect the composition of defensive lignins and other wall-bound phenolics. Substrate specificity appears differently depending on the CAD isoform, which contributes to revealing the biochemical properties of CAD proteins that regulate lignin synthesis. In this review, details regarding the expression and regulation of the CAD family in lignin biosynthesis are discussed. The isoforms of the CAD multigenic family have complex genetic regulation, and the signaling pathway and stress responses of plant development are closely linked. The synthesis of monolignol by CAD genes is likely to be regulated by development and environmental cues as well.

• Applied Biological Chemistry
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• v.45 no.2
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• pp.124-127
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• 2002

• Journal of the Korean Wood Science and Technology
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• v.45 no.3
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• pp.278-287
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• 2017

In this study, lignin was efficiently degraded via two-step catalytic cracking process and lignin-oil, char, and gas was produced as lignin degraded products. Three kinds of catalysts (MgO, CaO, and Pt/C) were used in first catalytic cracking step and the highest lignin-oil yield (76.2 wt%) was obtained in Pt/C catalyst with the smallest char formation (4.1 wt%). GC-MS/FID analysis revealed that 18 kinds of monomeric phenols existed in lignin-oil and sum of them was the highest in Pt/C condition (97.8 mg/g lignin). Meanwhile, relatively lower yield of monomeric phenols was produced in MgO and CaO condition because of their absorption on catalysts. Lignin-oil produced over Pt/C was introduced to second catalytic cracking process with porous Pd/activated carbon aerogel catalyst. From this process, four kinds of monomeric phenols such as 4-ethylguaiacol, 4-propylguaiacol, 4-ethylsyringol, 4-propylsyringol were selectively produced at 0.89 - 1.82 wt% level.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.10
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• pp.568-574
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• 2017

The purpose of this study was to optimize experimental conditions (time ($X_1$) (ranging of 26.36 - 93.64 min), concentration of sulfuric acid ($X_2$) (ranging of 0-2.5%) and temperature ($X_3$) (ranging of $136.4-203.6^{\circ}C$) for an organosolv pretreatment process to extract lignin from waste wood. The resulting quadratic model equation using RSM (response surface methodology) represented y (lignin yield) = $-79.89+0.91X_1+9.8X_2-2.54{\times}10^{-3}X_1{^2}-2.11X_2{^2}$. The $R^2$ (coefficient of determination) value of 0.8531 for a model indicates this model has statistically significant predictors at the 10% levels. The predictive results optimized by quadratic model produced a lignin yield of 12.46 g/100 g of dry wood under conditions of $178.2^{\circ}C$ and 2.32% $H_2SO_4$. The lignin yield was more affected by the acid catalyst concentrations than the reaction temperature, but the reaction time was not an influential factor for improving lignin extraction from waste wood in this organosolv pretreatment. According to ANOVA (analysis of variance), the significance probability (p-value) of model was smaller than 0.001 and simulation of obtained model equations showed a good reproducibility based on actual organosolv tests under optimal conditions.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.133-139
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• 2000

In this study, activated carbon was prepared from solid residue after lignin pyrolysis by using zinc chloride as an activation agent. The steam activation method was adopted to manufacture activated carbon from solid residue after lignin pyrolysis. The effect of process operation variables such as activation temperature, activation time and mass of activation agent added to char on the pore structure and specific surface area of the activated carbon was investigated. Activated carbon with high surface area and well-developed pore structure could be prepared, when solid residue after lignin pyrolysis was mixed with zinc chloride of 300 wt% and then the mixture was activated for 1 hour at $1000^{\circ}C$ in a stream of nitrogen.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.411-415
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• 2020

In this article, the preparation of hydrogels containing conducting polymer@lignin hybrids and their application to sensing materials were demonstrated using diverse techniques. A conducting polymer, polypyrrole (PPy) was polymerized on the surface of lignin and successful formation was analyzed with Fourier-transform infrared spectroscopy and scanning electron microscopy. Subsequently, PPy@lignin hybrids were mixed with a hydrogel matrix to obtain a conductive hydrogel. The feasibility of using the hydrogel as a sensing material was shown by obtaining reasonable sensing signals using various electrical measurements when adding solvents and solutions to the sensor system. The significance of sensor signals was confirmed with complementary experiments. This study shows that the hydrogel containing the PPy@lignin could be used for sensor applications.

• KSBB Journal
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• v.5 no.1
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• pp.81-85
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• 1990

Lignin was extracted from the rice straw by using the solvent mixture of buthyl alcohol and distilled water. And the experiment of vanillin production from extracted lignin was performed with the oxidation catalysts; CuO, Cu(OH)2 and CuSO4.5H2O. The optimum conditions of lignin extraction are the reaction temperature 12$0^{\circ}C$ and the mixture of 250mL buthyloloohol, 250mL, distilled water and 25g rice straw in the presence of 2.5g p-toluenesulfonic acid. The yield of vanillin from extracted lignin increased linearly with the increase of reaction temperature. And it increased with the order of Cu(OH)<$_2$ CuO$_4\cdot \;5H_2$Oas oxidation catalysts. The maximum yield of vanillin was 9% in the presence of 2.5%(w/v) CuSO$_4\cdot \;5H_2$O under the following conditions: temperature, 18$0^{\circ}C$; pressure, 13atm; pH 4.0 and reaction time, two hours.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.761-762
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• 2000

Waste newspaper is many part of Municipal Solid Waste(MSW). Newspaper consist of cellulose, hemicellulose and lignin which biomass components. We could get various compound usable as fuel when pyrolysis of lignin. Therefore, we should get similar phenomena with pyrolysis of newspaper. Highest conversion rate when acetone was used as pyrolysis solvent was $350 {\sim}400^{\circ}C$, $40{\sim}50$minutes.