• Journal of the Korean Wood Science and Technology
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• v.8 no.3
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• pp.64-76
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• 1980

Fig. 8 summarizes the present status of high yield pulp production and the directions of research on modification. A thick line indicates pulping process presently in use. As mentioned previously, one kind of modification is to introduce hydrophilic groups onto the pulp. Still unsolved is whether or not the introduction of hydrophilic groups should be restricted to lignin only. Goring (28) reported that middle lamella lignin has fewer phenolic hydroxyl groups than cell wall lignin and suggested that such a difference in the lignin may be useful in the removal of middle lamella lignin. The introduction of hydrophilic groups onto pulp may not be enough to modify high yield pulp. The removal of some portion of carbohydrate may be also necessary from the standpoint of softening of pulp fibers. There is no information at what lignin and carbohydrate, and how much should be removed. The combination with synthetic high polymers may also be important in modifying high yield pulp. Prof. C. Schuerch of the State University of New York who was a visiting professor at the University of Tokyo in 1974, mentioned that the hydrophilicity of lignin would be promoted, if phenolic hydroxyl or carboxyl groups could be introduced into the aromatic nucleus of lignin. If this were possible. this process would also mean a pulp yield of more than 100%. This idea is just one example of the expectation made possible through lignin chemistry. Instead of the introduction of hydrophilic group, the oxidative degradation of aromatic nucleus of lignin may also be useful in promoting the hydrophilicity of pulp. In this case, ozone may be an excellent chemical. However, there are a lot of problems to be solved such as homogeneity of reaction and selectivity of ozone for lignin. The above ideas are summarized in Fig. 9. There are many problems to be solved in the production of an excellent high yield pulp which is comparable to chemical pulp. The information from wood chemistry hopefully will elucidate some of the problems mentioned above.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.3
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• pp.447-452
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• 2016

It is imperative to develop an effective pathway to depolymerize lignin into liquid fuel that can be used as a bioheavy oil. Lignin can be converted into liquid products either by a solvent-free thermal cracking in the absence air, or thermo-chemical degradation in the presence of suitable solvents and chemicals. Here we show that the solvent-assisted liquefaction has produced promising results in the presence of metal-based catalysts. The supercritical ethanol is an efficient liquefaction solvent, which not only provides better solubility to lignin, but also scavenges the intermediate species. The concentrated sulfuric acid hydrolysis lignin (CSAHL) was completely liquefied in the presence of solid catalysts (Ni, Pd and Ru) with no char formation. The effective deoxy-liquefaction nature associated with scEtOH with aid hydrodeoxygenation catalysts, resulted in significant reduction in oxygen-to-carbon (O/C) molar ratio up to 61%. The decrease in oxygen content and increase in carbon and hydrogen contents increased the calorific value bio-oil, with higher heating value (HHV) of $34.6MJ{\cdot}Kg^{-1}$. The overall process is energetically efficient with 129.8% energy recovery (ER) and 70.8% energy efficiency (EE). The GC-TOF/MS analysis of bio-oil shows that the bio-oil mainly consists of monomeric species such as phenols, esters, furans, alcohols, and traces of aliphatic hydrocarbons. The bio-oil produced has better flow properties, low molecular weight, and high aromaticity.

• Korean Journal of Environmental Agriculture
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• v.7 no.2
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• pp.136-145
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• 1988

To investigate the seasonal changes of various organic and inorganic compounds in compost, carbon compounds in compost were analyzed at various composting periods. Contents of organic matter, cellulose, total carbon, organic carbon and biodegradable carbon in compost were decreased with the progress of composting. In contrast, contents of lignin and nonbiodegradable carbon were increased a little with the progress of composting, but effective contents of lignin were decreased with the lapse of composting time, while effective contents of nonbiodegradable carbon were not changed. Total carbon contents in organic matter in compost were decreased within 9 weeks after composting, and then increased thereafter. Difference between average values of total and biodegradable carbon contents was 6.2%. Actual decay rates of all the carbon compounds were higher than decay rates of the compounds at all the experimental periods. Both of actual decay rate and decay rate of all the carbon compounds were increased rapidly within 2 weeks after composting, and thereafter the rates were increased slightly with the lapse of composting time. Especially the decay rates of cellulose were increased from 9 to 21 weeks after composting. Actual degradation capacity showed the same tendency to degradation capacity of all the carbon compounds in compost. Decay rate and degradation capacity of lignin in compost had minus values, while actual decay rate and actual degradation capacity had plus values. Highly positive correlations were observed among organic matter, cellulose, total carbon and biodegradable carbon one another. Nonbiodegradable carbon showed highly negative correlation with organic matter, cellulose, total carbon, organic carbon and biodegradable carbon, respectively. The same tendencies were observed between lignin and organic matter, cellulose, total carbon, organic carbon and biodegradable carbon. Highly positive correlation was observed between lignin and nonbiodegradable carbon in compost.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.424-430
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• 2012

In this study, laccase activity, rate of weight loss and degree of lignin degradation of pine wood chips were determined during the liquid and solid state incubation with Polyporus brumalis. The results showed that laccase enzyme activity at untreated wood chip was gradually decreased after 20 days, but enzyme activity with wood chip treatment showed 10 times higher than untreated ones at 60 incubation days. Rate of weight losses of pine chip and rate of lignin loss were 23.4% and 6.3% by P. brumalis during 80 incubation days. Gene expression of pblac1 from P. brumalis was 3 times increased under pine chip treatment at 40 incubation days. Consequently, laccase activity of white rot fungi, P. brumalis, was increased at incubation with wood chip and pblac1 gene was important factor of lignin degradation. Therefore, to regulate lignin degrading enzyme gene expression by using the tools of biotechnology will be able to develop superior strains and it will be useful for pretreatment of lignocellulosic biomass at bioethanol production.

• Journal of Conservation Science
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• v.1 no.1 s.1
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• pp.3-11
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• 1992

Micromorphological changes in waterlogged archaeological woods excavated from Sweden and Germany were investigated. Especially bacterial attacks on those wood samples under near anaerobic conditions were examined by transmission electron microscopy(TEM). The major feature of micromorphological alterations in those wood samples was the preferential destruction of secondary wood cell wall. In contrast, the middle lamella was not extensively degraded. Three distinct degradation patterns by bacteria were observed : erosion, cavitation and tunnelling bacteria. Erosion and cavitation bacteria attacked primarily $S_2$ layer, whereas tunnelling bacteria made the tunnel-like degradation along the $S_1$ layer. Tunnelling bacteria, in some samples, were able to degrade tunnel in the lignin-rich areas, such as middle lamella, suggesting that these bacteria had the capacity to degrade the lignin. IR spectra indicate that hemicellulose and cellulose in the waterlogged woods were preferentially decomposed. Breakdown of the lignin, on the other hand, was much slower.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.759-763
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• 2000

Cell-free culture broth of Phanerochaete chrysosporium has been adopted to biologically degrade 2,4,5-trichlorophenol. Two different medium compositions of nitrogen-sufficient and nitrogen-limited were compared for their distribution of isozymes, activity of lignin peroxidase, and production of oxalate. The two different culture broths were tested for their ability to degrade 2,4,5-trichlorophenol, and the biodegradation efficiency was estimated in terms of the disappearance of 2,4,5-trichlorophenol. The degradation efficiency for the nitrogen-limited culture broth was higher than that of the nitrogen-sufficient culture broth, since the nitrogen-limited culture broth induced lignin peroxidases (LiPs) and manganese peroxidases (MnPs), and contained sufficient oxalate for producing necessary radicals. Finally, the possible mechanism of 2,4,5-CP degradation using the nitrogen-limited culture broth was proposed.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2010.04a
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• pp.79-92
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• 2010

In the presence of laccase, generation of monomeric aromatic acids from nonphenolic lignin model dimer veratrylglycerol-$\beta$-vanillate ether (VVE) was observed. The addition of acetovanillone (AV) or acetosyringone (AS) intensified this process, i.e. transformation was more extensive than in the experiments omitting mediators. Among the products isovanillic (IA) and vanillic (VA) acids were identified.

• Mycobiology
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• v.39 no.1
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• pp.64-66
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• 2011

Most fungi possess several hydrogen peroxide-generating enzymes, glucose oxidase and pyranose oxidase. Pyranose oxidase can use glucose as its substrate to generate hydrogen peroxide. White rot fungi, which degrade diverse recalcitrant compounds, contain lignin-degrading enzymes, and lignin peroxidase and manganese peroxidase require hydrogen peroxide for their enzymatic reactions. In this study, we isolated a cDNA fragment of pyranose oxidase from Phlebia tremellosa using PCR and examined its expression under the degradation conditions of diethylphthalate (DEP). Pyranose oxidase expression was enhanced up to 30% by the addition of DEP, and this result supports the possible involvement of pyranose oxidase in the degradation of recalcitrant compounds.

• The Korean Journal of Food And Nutrition
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• v.4 no.1
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• pp.99-107
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• 1991

Lignocellulose and lignolic compounds were absolutely given much weight In the biosphere, and their degradation was essential for continuous biological carbon circulation. Whereas aerobic cellulolytic microorganism dissolved the cellulose into their elements in the first stage, strict anaerobic cellulolytic microorganism's role was taken I increasing interest through the recent research. It was reviewed that anaerobic microbial degradation process of lignocellulose and its derivatives (cellulose, lignin, oligolignol and monoaromatic compound), and function of anaerobic microorganism on the. environmental ecology.

• Advances in environmental research
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• v.4 no.4
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• pp.247-262
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• 2015

The few lignin biomarker studies conducted in tropical environments are hampered by having to use references signatures established for plants and soils characteristic of the temperate zone. This study presents a lignin biomarker analysis (vanillyls (V), p-hydroxyls (P), syringyls (S), cinnamyls (C)) of the dominant plant species and soil horizons as well as an analysis of the interrelated terrigenous organic matter (TOM) dynamics between vegetation and soil of the $Tapaj{\acute{o}}s$ river region, an active colonization front in the Brazilian Amazon. We collected and analyzed samples from 17 fresh dominant plant species and 48 soil cores at three depths (0-5 cm, 20-25 cm, 50-55 cm) from primary rainforest, fallow forest, subsistence agriculture fields and pastures. Lignin signatures in tropical plants clearly distinguish from temperate ones with high ratios of Acid/aldehyde of vanillyls ((Ad/Al)v) and P/V+S. Contrary to temperate environments, similarly high ratios in tropical soils are not related to TOM degradation along with pedogenesis but to direct influence of plants growing on them. Lignin signatures of both plants and soils of primary rainforest and fallow forest clearly distinguish from those of non-forested areas, i.e., agriculture fields and pastures. Attalea speciosa Palm trees, an invasive species in all perturbed landscapes of the Amazon, exhibit lignin signatures clearly distinct from other dominant plant species. The study of lignin signatures in tropical areas thus represents a powerful tool to evaluate the impact of primary rainforest clearing on TOM dynamics in tropical areas.