• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.441-446
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• 2018

Herbaceous biomass is easier at chemical conversion than woody biomass. However, pretreatment must be needed because it has substantially lignin. Organsolv is good at fractionation of enzymatic hydrolysis inhibitors such as lignin and it is reusable by distillation when it has low molecular weight. Flow-through process can prevent recondensation of fractionated components and easily separate liquid from the biomass. In this study, the pretreatment was performed for decreasing additional process by using ethanol without catalyst because this process has a lot of operation expense at bio-alcohol production process. Flow-through pretreatment was performed at $150{\sim}190^{\circ}C$ with 30~99.5 wt% ethanol during 20~60 minutes. Also the phsyco-chemical pretreatment was performed for decreasing reaction time and temperature.

• Journal of the Korean Wood Science and Technology
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• v.16 no.4
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• pp.70-78
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• 1988

To separate and utilize the main components of hardwood (Quercus mongolica) by organosov pulping (ester pulping), chips were cooked at various conditions such as; the solvent ratio (acetic acid: ethylacetate: water, 50:25:25; 33:33:34; 25:50:25), maximum temperature (165, 170, $175^{\circ}C$), and cooking times (2, 2.5, 3 hr). The pulps were bleached by the sequences of CEDED, C/DEDED, PEDED. Lignin, sugars, and acetic acid were separated from black liquor and washing liquors. 1. The selective delignification at optimal pulp yield (43-45%) was obtained by cooking at acetic acid: ethylace tate: water ratio of 33:34:34 for 3 hr at $170^{\circ}C$. But in this case, kappa no. of the pulp was not reduced under 60 points. 2. Kappa no. of the pulp could be dropped by an acetone wash to remove reprecipitated lignin a t cooked pulp. 3. The unbleached pulps had a brightness of 45-50%, whereas the bleached pulps gave at 88-93% brightness. Tensile, burst, and tear strengths of the bleached pulps were lower than those of kraft pulp, especially in tear strength. The pulps which were bleached with CEDED sequence were higher in strengths than another bleaching sequences. 4. Lignin of 90-95%(lignin base on wood)was separated from black liquor and washing liquors, while the purified sugars and recovery of acetic acid were a low. An organic phase composed of acetic acid, ethylacetate, and water was separated to a two-phase system by proper adjustment of the solvent ratios.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.218-230
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• 2016

The effect of steam explosion coupled with alkali (1% sodium hydroxide, 1% potassium hydroxide and 15% sodium carbonate) or organosolv solvent (85% methanol, 70% ethanol and dioxane) on the production of sugar, changes in the chemical composition of M. sinensis were evaluated. The steam explosion coupled with 1% potassium hydroxide and dioxane were better as compared with other treatments based on the removals of acid insoluble lignin, and about 89.0% and 85.4%. Enzymatic hydrolysis of steam explosion with 1% potassium hydroxide and dioxane treated M. sinensis, gave a 98.0% and 96.5% of glucose conversion, respectively. These results suggested that pretreatment of M. sinensis with either potassium hydroxide or dioxane could be a promising pretreatment method for glucose production.

• KSBB Journal
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• v.29 no.3
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• pp.193-198
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• 2014

Pretreatment of wastepaper using aqueous glycerol under high pressure was studied to enhance the enzymatic hydrolysis. The pretreatment was conducted over a wide range of conditions including temperatures of $150{\sim}170^{\circ}C$, sulfuric acid concentrations of 0.5~1.5%, and reaction times of 30~90 minutes. After the effect of glycerol concentration on the pretreatment performance was investigated, 70% glycerol was selected. As glycerol concentration was increased, higher digestibility was achieved due to higher lignin removal. The optimum condition was found to be around $160^{\circ}C$, 1%, and 60 minutes. At this condition, 60% and 35% of hemicellulose and lignin, respectively, were removed, while only 5% of cellulose was lost. The enzymatic digestibility was 76%, meaning that 73% of the glucan present in the initial substrate was recovered as glucose after enzymatic hydrolysis. Also, it was found that the temperature and acid concentration than the reaction time were more strongly related to the compositional removals and enzymatic digestibility.

• KSBB Journal
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• v.28 no.1
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• pp.48-53
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• 2013

Pretreatment of wastepaper using aqueous glycerol was investigated to enhance the enzymatic hydrolysis. The effects of four factors (solid/liquid ratio, glycerol concentration, acid concentration, and reaction time) on the dissolution yield, the removal of cellulose, hemicellulose and lignin, and the enzymatic digestibility were examined at $150^{\circ}C$. The 1/8 of solid/liquid was determined to perform the reaction uniformly, and the 93% of glycerol concentration was found to be a minimum concentration to conduct the reaction under atmospheric pressure. Also, it was found that the acid concentration and reaction time were strongly related to the dissolution yield and the removal of cellulose, hemicellulose and lignin, but moderately to the enzymatic digestibility. At an optimum condition of $150^{\circ}C$, 1 h and 1% acid concentration, 56% and 49% of hemicellulose and lignin, respectively, were removed, while only 4% of cellulose was removed. The enzymatic digestibility at this condition was 86%, meaning that 83% of the glucan present in the initial substrate was converted to glucose. Compared to glycerol with ethylene glycol as a pretreatment solvent, glycerol is much cheaper than ethylene glycol, but ethylene glycol is superior to glycerol in delignification.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.119-126
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• 2016

In this study, we separated the lignin from the wood by using the high boiling point solvent for developing more environmental friendly pulping method. High boiling point solvents as Ethers, glycols and ketones were used to remove the lignin in the pine wood meals. The Yield and lignin content of residual wood meals was reduced according to the input of the catalyst. Me-C, E-Ca, TEG and MIBK had the best delignification rate of 9 kinds of high-boiling point solvents. At the hydrolysis ratio of the selected solvents, The TEG was highest remain ratio of carbohydrates and the E-Ca was lowest remain ratio of lignin. And the Me-C was most excellent lignin hydrolysis ratio at the low catalyst. The selectivity of delignification of Me-C, E-Ca, TEG and MIBK solvents were 49.6, 49.9, 53.8 and 53.1%, respectively, and its values were similar to those of the commercial Kraft Pulp.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.1
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• pp.79-88
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• 2008

The production of bioethanol, which is one of the alternative fuel, cause the various problem such as agflation in human society. As a substitute for the feedstock, lignocellulosic biomass have a big potential. However, bioethanol production with cellulosic material is not commercialized due to high cost. Thermochemical pretreatment to improve the rate of enzyme hydrolysis and increase the recovery of fermentable sugar, is required in order to achieve the cost down in bioethanol production. In this study, various problems and technologies for pretreatment is introduced. Acid hydrolysis, alkali hydrolysis, steam explosion, organosolv process, ammonia explosion, and wet oxidation pretreatment remove lignin and hemicellulose, and reduce cellulose crystallinity. Optimization of pretreatment process on various sources of lignocellulosic biomass such as softwood, hardwood, and straw should be performed.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.124-134
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• 2016

The main goal of this study was to investigate biomodification mechanism of lignin by white rot fungus, Abortiporus biennis, and to depolymerize ethanol organosolv lignin for industrial application. In nitrogen-limited culture, A. biennis polymerized mainly lignin showing a rapid increase of molecular weight and structural changes depending on incubation days. At the initial incubation days, cleavage of ether bonds increased phenolic OH content, while the results were contrary in of the later part of the culture. Based on these results, ascorbic acid as a reducing agent was used to induce depolymerization of lignin during cultivation with white rot fungus. As a result, the degree of increase of average molecular weight of lignin was significantly declined when compared with those of the ascorbic acid free-experiment, although the molecular weight of fungus treated sample slightly increased than that of control. Furthermore, lignin derived oligomers in culture medium were depolymerized with the addition of ascorbic acid, showing that the average molecular weight was 381 Da, and phenolic OH content was 38.63%. These depolymerized lignin oligomers were considered to be applicable for industrial utilization of lignin. In conclusion, A. biennis led to the polymerization of lignin during biomodification period. The addition of ascorbic acid had a positive effect on the depolymerization and increase of phenolic OH content of lignin oligomers in medium.