• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.8-16
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• 2002

This study was performed to produce the high reactive lignin zero substrates from autohydrolyzed wood resources. In chemical compositions of used raw-materials, there were significant differences between two species, Japanese larch (Larix leptolepis) and oak (Quercus mongolica) woods. Japanese larch contained 25 to 3.5 times higher amounts of extractives than oak wood, which is mainly derived from high content of arabinogalactan in Japanese larch wood. Oak wood has 5% lower lignin content and 3% higher holocellulose and pentosans than larch wood. Concerned to changes in wood components during autohydrolysis pretreatment at 22 kg/cm² steaming pressure for 5~60 min, glucose content was constant during pretreatment, while hemicellulose and lignin were abruptly changed. Hemicellulose fraction was decreased significantly and lignin contents increased because of its condensation reaction with hemicellulose degradation products. The pH of hydrolyzates during pretreatment was decreased, reached upto pH 3 and since then leveled off. In the case of oak wood, same tendency was observed as in Japanese larch. Autohydrolysis followed by sodium chlorite and sulfite or bisulfite pretreatment was very effective in delignification of the substrates. In particular, two-stage delignification of autohydrolyzed woods with alkali and O₂-alkali resulted in very low lignin content substrates, such as 0~0.2% lignin substrate.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.48-59
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• 2018

This study was conducted to suggest the effective management and recycling processes of coffee waste, which can be easily obtained from coffee shops and coffee-related products industries. Prior to the fabrication of pellets, the potential of coffee waste as a raw material of pellet was investigated through the examination of its chemical compositions and fuel characteristics. Major gradient included in coffee waste was holocellulose, followed by fat/oil and protein. Coffee waste contained a small quantity of ash (0.7%), such as calcium, sodium, potassium and magnesium. Interestingly, coffee waste was easily dried probably due to its porous structure. Pellets fabricated with coffee waste and larch sawdust showed good fuel characteristics, such as moisture content, ash content, density and durability. The pellets exceed greatly the minimum requirements of $1^{st}$-grade wood pellet standard designated by National Institute of Forest Science (NIFOS). Particularly, the high calorific value of coffee waste showed the potential as a raw material of pellet. However, owing to high nitrogen and sulfur contents, coffee waste is like to be used as a raw material of wood pellet for combined heat and power plants equipped with a reduction system of $NO_x$ and $SO_x$ gases. On the other hand, 91 wt% larch sawdust and 9 wt% coffee waste are required to fabricate the $1^{st}$-grade wood pellets designated by NIFOS. Pellets fabricated with the conditions are estimated to have nitrogen content of 0.298% and sulfur content of 0.03%. Lastly, if amounts of coffee waste and sawdust in the production of wood pellets are adequately adjusted according to its purchasing price, the manufacturing cost of pellet can effectively be reduced. In addition, it is expected tp prepare the effective recycling process of waste and to relieve the environmental burden with the reduction of waste from the commercialization of coffee waste/larch pellets.

• Journal of Korean Society of Forest Science
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• v.49 no.1
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• pp.1-5
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• 1980

In this study, enzymatic saccharification of substrates from Alnus hirsuta Ruper (8-14 years). Quercus acutissima Carruthers, Betula platyphylla var. japonica Nera, Populus euramericana Guiner and Platanus orientalis L. were investigated using crude cellulase preparations of Trichoderma viride Pers. ex. Fr. SANK 16374, and conduced on the optimum treated conditions of the cellulase sacchrification and reactivation of residue of digested substrates. The Trichoderma viride cellulase was produced by the submerged culture process and produced in the culture fluid was salted out quantitatively by the use of ammonium sulfate. The method of dilignification from wood (5 species) was treated by the peracetic acid(PA) method. The reducing sugar was determined by the dinitrosalicylic acid (DNS) method. 1. The results of tests carried out for 96 hr. (Figure 1), show conclusively the initial substrates from 5 species ($S_3$) which has been rendered highly reactive form and the mean rate of reducing sugar was 28.3 %. 2. The results of tests carried out for 96 hr., the reactivation of residue of digested substrates (improvement in the quality of the substrate through preheating in air at $190^{\circ}C$. for 45 min. followed by milling was (60 mesh size) at the same substrate level, increased concentrations of cellulase at the same substrate level, and increased concentrations of cellulase increases the rate of hydrolysis considerably. 3. Figure 1. shows conclusively that the residue of digested substrates ($S_1$ dried at $60^{\circ}C$) which has been rendered extremly resistant to cellulase action can be reactivated into a highly reactive form ($S_2$), almost comparable to that of the initial substrates ($S_3$). And the reducing sugar formation did not show statistically significent differences at 5% levels by initial substrates and the residue of digested substrates (preheating in air at $190^{\circ}C$. for 45 min. fallowed by milling was (60 mesh size).