• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.18-24
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• 2012

Lignocellulose is difficult to hydrolyze due to the presence of lignin and the technology developed for cellulose fermentation to ethanol is not yet economically viable. However, recent advances in the extremely new field of biotechnology for the ethanol production are making it possible to use of Agriculture residual biomass, e.q., Barley straw, because of their several superior aspects as Agriculture residual biomass; low lignin, high contents of carbohydrates. Barley straw consists of 39.78% cellulose (glucose), 22.56% hemicelluloses and 19.27% lignin. Pretreatment of barley straw using NaOH pretreatment solutions concentration with 2%, temperature $85^{\circ}C$ and reaction times 1 hr were investigates. $NH_4OH$ pretreatment condition was solutions concentration with 15%, temperature $60^{\circ}C$, and reaction times 24hr were investigates. Furthermore, enzymatic saccharification using cellulose at $50^{\circ}C$, pH 4.8, 180 rpm for conversion of cellulose contained in barley straw to monomeric sugar. The pretreatment of barley straw using NaOH and $NH_4OH$ can significantly improve enzymatic saccharification of barley straw by extract more lignin and increasing its accessibility to hydrolytic enzymes. The result showed NaOH pretreatment extracted yield of lignin was 24.15%. $NH_4OH$ pretreatment extracted yield of lignin was 29.09%. Shaccharification of barley straw pretreatment by NaOH for 72hr and pH 4.8 result in maximum glucose concentration 15.39g/L (58.40%) and by $NH_4OH$ for 72hr and pH 4.8 result in maximum glucose concentration 16.01g/L (64.78%).

• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.20-27
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• 2001

An effective method for production of glucose was developed using enzymatic hydrolysis of Suwon poplar by the cellulase. Enzymatic hydrolysis of wood is the reaction to produce glucose from wood using enzyme which derives from microorganism. Glucose can be transferred easily to ethanol by fermentation. Ethanol is the starting material for producing acetone, butanol, citric acid and lactic acid. The mechanism of the enzymatic hydrolysis of cellulose are reasonably explained in terms of the sequential action of three different types of enzymes, endo-cellulase, ex-cellulase, and $\beta$ -glucosidase. The goal of this work was to investigate the cellulose hydrolysis pretreated polar with various concentration NaOH, the crystallinity of cellulose, lignin contents and the degree of hydrolysis.

• Journal of the Korean Wood Science and Technology
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• v.28 no.4
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• pp.17-24
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• 2000

The peroxidase activity was localized cytochemically to get an insight into its precise function in lignin biosynthesis. In this work, cerium chloride ($CeCl_3$) was used as a trapping agent for hydrogen peroxide ($H_2O_2$) generated from peroxidase. Seasonal variation of peroxidase activities in cambial region of Populus, Pinus, and Ginkgo was investigated at subcellular levels. Under transmission electron microscopy, electron dense deposits of cerium perhydroxide formed by reaction with $H_2O_2$ were observed in cambium and its immediate derivatives. The staining with $CeCl_3$ in cambium varied with growth seasons. The strongest $H_2O_2$ accumulation, regardless of tree species, appeared in May. Staining pattern of $CeCl_3$ in the cambium of poplar indicated that the production of peroxidase started in March before the opening of buds and reached the highest in May and then declined in August. Ginkgo and Pinus showed relatively late generation of $H_2O_2$ production when compared with Populus. Although Ginkgo and Pinus are classified into gymnosperms, however, the generation of peroxidase production and its duration was different from each other. Little staining appeared in all the tree samples collected in September before falling the leaves.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.115-119
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• 1999

During mechanical pulp production and blcaching wood components, such as extractives, carbohydrates and lignin are dissolved and dispersed into the process waters. These components are called dissolved and colloidal substances(DCS). DCS can accumulate during water circulation and can in turn affect paper machine runnability and also the strength and optical properties of the paper. In this work DCS fraction origination from TMP process were treated with enzymes acting on triglycerides. glucomannans, and lignin and the effect of enzymatic treatments on the water composition as well as sheet properies were evaluated. Lipases were found to modify the chemical structure of the extractives resulting in more hydrophilic fibre surface and subsequent improvement in the sheet strength properties. Mannanase treatment, on the other hand, destabilized pitch. As a result, aggregation of pitch to the fibres was observed which in turn resulted in impaired strength properties. Laccase could effectively polymerize lignans and the reaction products seemed to be sorbed onto the fibres.

• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.1-7
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• 2003

The phase transformation from cellulose I into cellulose II in woods by way of Na-cellulose I was examined by x-ray diffraction analysis.The formation of Na-cellulose I in woods increased with the increase of treating time in alkali solution. When compression wood was treated with 20% NaOH solution at room temperature for 1 day, the x-ray diagram showed only Na-cellulose I. On the other hand, the x-ray diagram of tension wood showed a mixture of cellulose I and Na-cellulose I. Cellulose I of tension wood could not be transformed completely into Na-cellulose I even after 10-day treatment, but was transformed into Na-cellulose I after 30-day treatment. Na-cellulose I of compression and tension woods was converted to the cellulose I pattern and the mixture of cellulose I and cellulose II, respectively, after washing with water and drying at 20℃. Cellulose I regenerated from Na-cellulose I in wood could not be converted to cellulose II by delignification. Thus, it revealed that the delignification of the alkali-treated wood did not affect their cellulose structures. From the results, therefore, it can be concluded that lignin in woods prevents the formation of the stable Na-cellulose I and the conversion from cellulose I to cellulose II. This means that the conversion of chain polarity of wood cellulose hardly occurs during mercerization because cellulose microfibrils are fixed by lignin which not to be intermingled.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.292-296
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• 2011

Liberation of fermentable sugars from lignocellulosic biomass is one of the key challenges in production of cellulosic ethanol. Aqueous ammonia cleaves ether and ester bonds in lignin carbohydrate complexes. It is an effective swelling reagent for lignocellulosic biomass. The aqueous ammonia pretreatment selectively reduces the lignin content of biomass. However, at high temperatures, this process solubilizes more than 50% of the hemicellulose in the biomass. Here we conducted a SAA(Soaking in Aqueous Ammonia) process by moderate reaction temperatures at atmospheric pressure using various lignocellulosicbiomass. The optimum condition of this process was 15 wt% of aqueous ammonia at 50 of reaction time during 72 hr. The delignification was up to 60% basis on initial biomass and the enzymatic digestibility was 60-90% for agricultural biomass, respectively.

• Journal of Korea Foresty Energy
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• v.24 no.1
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• pp.39-46
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• 2005

In this study, the possibility of sugar conversion of poplar wood(Populus $alba{\times}rglandulosa$) and their degradation features of major wood components were characterized using flow type supercritical water treatment system. The finely ground poplar wood meals were treated for 2min. under subcritical condition$(23MPa,\;275^{\circ}C\;and\;325^{\circ}C)$ and supercritical condition $(23MPa,\;375^{\circ}C\;and\;415^{\circ}C)$. respectively. The degradation products of poplar wood meals appeared brownish colors, including undegraded solids. Increasing the temperature of the system, the degradation rate of poplar wood meals was accelerated and reached up to $94\%\;at\;375^{\circ}C$. The total amount of reducing sugars in degradation products determined by DNS method were gradually lowered when the temperature condition became severe. This indicated that the reducing sugars formed were further degraded to kan derivatives by certain side reaction such as pyrolysis under higher temperature. In order to characterize degradation features of lignin, the degradation products were extracted with ethylacetate and the organic phases were subjected to GC-MS analysis. Main lignin degradation products were identified to vanillin, guaiacol, syrinaldehyde, 4-prophenyl syringol and dihydrosinapyl alcohol, which could be formed by the cleavage of ether linkages in lignin polymers by high temperature condition.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.79-86
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• 2005

Aspen wood (Populus tremuloides, L.) was biotreated with Ceriporiopsis subvermispora for 1, 2, 4, and 6 weeks to observe the physical/chemical modification of wood components. Milled wood lignins (MWLs) isolated from each decayed wood were analyzed by gel permeation chromatography (GPC) and nitrobenzene oxidation (NBO). As fungal treatment was progressed, lignin contents continuously decreased up to 20% after 6-week treatment. The lignin polymer could be fragmented to low-molecular phenolics, which make an enhancement of alkali solubility. Holocellulose contents were not affected severely during the period of fungal treatment, only reduction of 5~6% compared to the control. Xylose contents were decreased gradually from 23.4% to 18% after 6 weeks, whereas alpha-cellulose remained almost unchanged. Gel permeation chromatography (GPC) indicates that molecular weight of lignin undergoes a slight decrement for 4 weeks of fungal treatment. Nitrobenzene oxidation revealed that total yield of NBO products of lignins were lowered ca 20% after fungal treatment. Sum of syringaldehyde and syringic acid are remarkably decreased. However, increment of sum of vanillin and vanillic acid was surprisingly observed. These results work as indirect evidence that a specific lignolytic reaction, maybe selective demethoxylaytion of S-lignin, can occur during fungal treatment of aspen wood by C. subvermispora.

• Korean Journal of Food Science and Technology
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• v.19 no.4
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• pp.317-323
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• 1987

This study was undertaken to examine the applicability of domestic enzymes in the quantitative determination of dietary fibers according to the official enzymatic-gravimetric method of AOAC and to apply it to 4 kinds of fruits (apple, pear, peach and persimmon) and 4 kinds of vegetables (Korean radish, lettuce, Korean cabbage and cabbage Kimchi). With domestic enzymes, an optimum condition was selected to use 1/10 units of enzyme activity and to extent the reaction time two-fold as compared with the recommended method, in the case of fruits and vegetables. On a dry matter basis, fiber contents of fruits were in the range of 9.4-28.8% total dietary fiber, 1.8-7.8% non-cellulosic polysaccharides, 3.7-5.8% cellulose and 1.3-21.3% lignin. Fiber contents of vegetables were 26.0-35.7% total dietary fiber, 11.3-14.4% non-cellulosic polysac-charides, 12.3-19.7% cellulose and 1.4-7.4% lignin. On a dry matter basis, crude fiber contents were 3.5-6.7%in fruits and 9.1-13.8% in vegetables. Therefore, crude fiber contents of fruits and vegetables accounted for only 12-50% of total dietary fibers.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.87-93
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• 1993

This study was undertaken to investigate the characteristics and the productivities of lignin olytic enzymes: laccase (Lac) and Mn-dependent peroxidase (MnP) from Coriolus versicolor and Lentinus edodes respectively. Enzymes were isolated from cultural filterates and purified according to the standard methods. These enzymes showed one band in SDS-PAGE and their molecular weights were found 62,000 and 45,000 dalton respectively. Polyclonal antibodies against Lac and MnP were raised against mouse. In the ELISA (enzyme-linked immunosorbent assay), Lac and MnP-antiserum produced a strong positive reaction with Lac and MnP antigen($A_{405}$=2.50 and 3.53 respectively). The sera to negative (S/N) ratio was determined by the dividing the mean absorbance of antibodies by the corresponding diluted samples from normal mouse serum. The sera produced showed 2 times more positive reaction in S/N ratio than negative sera.