• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.274-286
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• 2009

Lignocellulosic biomass is the most abundant raw material for bioconversion in many country. However the high costs for pretreatment and enzymatic hydrolysis currently deter commercialization of lignocellulosic biomass, especially wood biomass which is considered as the most recalcitrant material for enzymatic hydrolysis mainly due to the high lignified structure and the nature of the lignin component. Therefore, overcoming recalcitrance of lignocellulosic biomass for converting carbohydrates into intermediates that can subsequently be converted into biobased fuels and biobased products is the primary technical and economic challenge for bioconversion process. This study was mainly reviewed on the research trend of pretreatment with lignocellulosic biomass in bioethanol production process.

• Journal of Forest and Environmental Science
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• v.26 no.2
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• pp.137-148
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• 2010

The high costs for ethanol production with lignocellulosic biomass as a second generation energy materials currently deter commercialization of lignocellulosic biomass, especially wood biomass which is considered as the most recalcitrant material for enzymatic hydrolysis mainly due to the high lignified structure and the nature of the lignin component. Therefore, overcoming recalcitrance of lignocellulosic biomass for converting carbohydrates into sugar that can subsequently be converted into biobased fuels and biobased products is the primary technical and economic challenge for bioconversion process. This study was mainly reviewed on the research trend of the enhancement of enzymatic hydrolysis for lignocellulosic biomass after pretreatment in bioethanol production process.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.5
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• pp.1-14
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• 2010

Bio-ethanol is a promising alternative energy source for reducing both consumption of crude oil and environmental pollution from renewable resources like lignocellulosic biomass such as wood, forest residuals, agricultural leftovers and urban wastes. Based on current technologies, the cost of ethanol production from lignocellulosic materials is relatively high, and the main challenges are the low yield and high cost of the hydrolysis process. Development of more efficient pretreatment technology (physical, chemical, physico-chemical, and biological pretreatment), integration of several microbiological conversions into fewer reactors, and increasing ethanol production capacity may decrease specific investment for ethanol producing plants. The purpose of pretreatment of lignocellulosic material is to improve the accessible surface area of cellulose for hydrolytic enzymes and enhance the conversion of cellulose to glucose and finally high yield ethanol production which is economic and environmental friendly.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.511-511
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• 2009

Lignocellulosic biomass is the most abundant organic material on earth and also promising raw material for bioenergy production. Agricultural residues in the process of bio-oil extraction, is an abundant and low-cost lignocellulosic material. The technology for conversion of lignocellulosic biomass resources to fuels and chemicals, such as ethanol, has been under development for decades. One of the well-studied technologies that are currently being commercialized is to use a dilute acid-catalyzed pretreatment followed by enzymatic hydrolysis and fermentation to produce ethanol. In this work, the dilute-acid hydrolysis of agricultural residues was optimized through the utilization of statistical experimental design. Evaluation criteria for optimization of the pretreatment conditions were based on high xylose recovery and low inhibitor contents in the hydrolyzates. The purpose of this study was to gain a more accurate understanding of the quantities of acid required for effective hydrolysis and the reactivity trade-offs with reaction time and temperature that will enable overall process optimization.

• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.59-67
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• 2001

Rice husk flours were analyzed by chemical composition and thermogravimetric methods in nitrogen atmosphere to discuss its feasibility as a raw material for manufacturing agricultural lignocellulosic fiber-thermoplastic polymer composite. It was revealed in the chemical composition analysis that rice husk flour was composed of moisture, 5.0%; lignin, 21.6%; holocellulose, 60.8%; ash, 12.6%. In the thermogravimetric analysis (TGA), thermal decomposition behavior of rice husk flour from room temperature to $350^{\circ}C$ was similar to that of wood flour, but rice husk flour was more thermally stable from 350 to $800^{\circ}C$ than wood flour because of higher silica content in the rice husk flour and smaller particle size of rice husk flour. The activation energy of thermal decomposition was evaluated using Flynn & Wall expression. As the thermal decomposition proceeded in rice husk flour, the activation energy of thermal decomposition appeared almost constant up to ${\alpha}=0.25$, but thereafter increased. Activation energy of thermal decomposition in wood flour, however, decreased steeply up to ${\alpha}=0.3$, but thereafter remained almost constant. From the results, rice husk flour was thought be a substitute for wood flour in manufacturing agricultural lignocellulosic fiber-thermoplastic polymer composite in the aspect of thermal decomposition.

• Journal of the Korean Wood Science and Technology
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• v.18 no.4
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• pp.18-25
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• 1990

As polysaccharides in lignocellulosic materials are encrusted with aromatic lignin molecules and have high crystallinity, these require pretreatment to improve their digestability by cellulolytic enzymes. Though a number of pretreatment methods have been proposed, the steam explosion process is evaluated as a promising method. This study was performed to investigate the effect of delignification treatment by alkali, methanol and the others on the enzymatic hydrolysis. Delignification treatment resulted in great increase rate in enzymatic hydrolysis. Concerning to the effect of delignication reagents on the enzymatic hydrolysis, methanol treatment was more effective than alkali in the case of oak wood. In pine wood, the delignification did not showed any significant enhancement of hydrolysis rate. Complete delignification by Alkali-Oxygen. Alkali treatment showed high saccharification rate of 99.5%.

• Plant Resources
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• v.8 no.3
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• pp.175-180
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• 2005

Thin sections of cellulose fibers were incubated with an endo- and an exoglucanase labeled with gold particles of differing sizes. The hydrolytic sites were then visualized under transmission electron microscopy (TEM). The potential interaction between the ${\beta}$-1, 4-glucan substrates and the endo- and the exoglucanases was investigated using cellulosic and lignocellulosic substrates. The simultaneous visualization was very successful in distinguishing preferred substrates for each cellulase in lignocellulosic substrates. When plant lignocellulose was preincubated with endocellulase, density of the gold labeling greatly increased suggesting that preliminary exposure of lignocellulosic material to endocellulase may have enhanced the accessibility of the substrate to endocellulase and exocellulase. This result provided a plausible explanation for the observed endo/exo cellulase co-hydrolysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.7 s.250
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• pp.794-799
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• 2006

In recent years, the use of natural fiber as reinforcement in polymer composites to replace synthetic fiber such as glass fiber is receiving increasing attention. Because of increasing usage according to the high demand, the cost of thermoplastic has increased rapidly over the past decades. We used a thermoplastic polymer(polypropylene) as the matrix and a lignocellulosic material(rice-husk flour) as the reinforcement filler to prepare a particle-reinforced composite to examine the possibility of using lignocellulosic material as reinforcement filler and to determine data of test results for physical, mechanical and morphological properties of the composite according to the reinforcement filler content in respect to thermoplastic polymer, In this study, PLA/PP rice-husk fiber-reinforced thermoplastic composites that made by the hot press molding method according to appropriate manufacturing process was evaluated as mechanical properties.

• KSBB Journal
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• v.20 no.4
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• pp.317-322
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• 2005

Various recovery methods were investigated to maximize hemicellulose recovery from lignocellulosic material hydrolyzed by pure water. The pretreatment conditions of water hydrolysis were $170\~180^{\circ}C$ and 1 hour of reaction time. The percentage of hemicellulose solubilized increased as the temperature increased from 170 to $180^{\circ}C$. However, significant decomposition of sugar was observed at temperature of $180^{\circ}C$. From the results of water hydrolysis, the total amount of glucan in solid residue and liquid hydrolyzate was close to the total glucan in the original biomass. For hemicellulose, however, there was a significant difference between both contents. To prove this difference, various recovery methods were proposed. From the total sugar accountability (sugar in liquid + sugar in solid), it was confirmed that hemicellulose recovery in the hydrolyzate was increased if the product including both hydrolyzate and solid residue was physically stimulated by such as heating and ultrasound irradiation. This indicated that, in commercial scale processes that much bigger substrate sizes are used and a sufficient amount of leaching solvent can not be used after pretreatment, a significant amount of oligomers could be trapped in the solid matrix.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.1-8
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• 2017

The production of high-value chemicals from natural resources as an alternative for petroleum-based products is currently expanding in parallel with biorefinery. The use of lignocellulosic biomass as raw material is promising to achieve economic and environmental sustainability. Filamentous fungi, particularly Aspergillus species, are already used industrially to produce organic acid as well as many enzymes. The production of lignocellulose-degrading enzymes opens the possibility for direct fungal fermentation towards organic acids such as itaconic acid (IA) and fumaric acid (FA). These acids have wide-range applications and potentially addressable markets as platform chemicals. However, current technologies for the production of these compounds are mostly based on submerged fermentation. This work showed the capacity of two Aspergillus species (A. terreus and A. oryzae) to yield both acids by solid-state fermentation and simultaneous saccharification and fermentation. FA was optimally produced at by A. oryzae in simultaneous saccharification and fermentation (0.54 mg/g wheat bran). The yield of 0.11 mg IA/g biomass by A. oryzae is the highest reported in the literature for simultaneous solid-state fermentation without sugar supplements.