• Journal of the Korean Wood Science and Technology
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• v.28 no.4
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• pp.29-40
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• 2000

Highly purified Cerrena unicolor laccase (benzenediol:oxygen oxidoreductase, EC 1.10.3.2) caused the demethoxylation of milled wood lignin and several lignin related substances. The constitutive form of the enzyme produced extracellularly by C. unicolor fermenter culture was isolated and purified by ion-exchange chromatography on the DEAE-Toyopearl column and by affinity chromatography on a ConA-Sepharose and Syringyl-AH-Sepharose 4B columns. The enzyme was further immobilized on functionalized porous glass (CPG) and keratin coated CPG. The demethylating activity was monitored both by estimation of released methanol and by detection of the level of methoxyl groups (also in some water miscible solvents) after incubation of lignin materials with laccase preparations (free and immobilized). The effects of the incubation time and temperature on the demethoxylating activity of immobilized laccase preparations were also studied.

• Journal of Applied Biological Chemistry
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• v.55 no.3
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• pp.141-148
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• 2012

Recently, concerns about the volatile hazardous compounds including acetaldehyde, methanol, and fusel oils in alcoholic beverages, which cause hangover such as headache and dizziness after consumption, have been raised. The volatile hazardous compounds might also lead to an increased incidence of liver diseases and even cancers with a high consumption of alcoholic beverages. Acetaldehyde is a volatile compound naturally found in alcoholic beverages and used as flavor in many foods. However this is also regarded as possibly being carcinogenic to humans. Furthermore, acetaldehyde with alcoholic consumption is recently classified as Group 1, carcinogenic to humans. On the other hand, methanol is generated from demethoxylation of pectin by pectinolytic enzyme during alcoholic fermentation. Higher alcohols occur naturally in alcoholic beverages as by-products of alcoholic fermentation and are generally regarded as important flavor compounds. In the current study, we reviewed on the health concern, maximum levels, analytical methods, and current levels of hazardous volatile compounds in alcoholic beverages.

• Journal of the Korean Wood Science and Technology
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• v.45 no.2
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• pp.168-181
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• 2017

Whole cell of Phanerochaete chrysosporium with reducing agent was applied to verify the degradation mechanism of aromatic compounds derived from lignin precisely. Unlike the free-reducing agent experiment, various degraded products of aromatic compounds were detected under the fungal treatment. Our results suggested that demethoxylation, $C_{\alpha}$ oxidation and ring cleavage of aromatic compounds occurred under the catabolic system of P. chrysosporium. After that, degraded products stimulated the primary metabolism of fungus, so succinic acid was ultimately main degradation product of lignin derived-aromatic compounds. Especially, hydroquinone was detected as final intermediate in the degradation of aromatics and production of succinic acid. In conclusions, P. chrysosporium has an unique catabolic metabolism related to the production of succinic acid from lignin derived-aromatic compounds, which was meaningful in terms of lignin valorization.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.86-94
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• 2011

Pyrolytic lignin was obtained from biooil produced with yellow poplar wood. Fast pyrolysis was performed under various temperature ranges and residence times using fluidized bed type reactor. Several analytical methods were adopted to characterize the structure of pyrolytic lignin as well as the effect of pyrolysis temperature and residence time on the modification of the lignin. The yield of pyrolytic lignin increased as increasing pyrolysis temperature and decreasing residence time of pyrolysis products. The molecular weight of pyrolytic lignin determined by gel permeation chromatography (GPC) was approximately 1,200 mol/g, which was approximately a tenth of milled wood lignin (MWL) purified from the same woody biomass. Based on analytical data, demethoxylation and side chain cleavage reaction were dominantly occurred during fast pyrolysis.