• Journal of the Korean Wood Science and Technology
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• v.19 no.1
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• pp.14-21
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• 1991

Steam-exploded woods were delignified by two-stage with a 0.3% NaOH extraction and oxygen-alkali bleaching and were subjected to the enzymatic hydrolysis with cellulase enzyme. Also, an improved almost quantitative recycle process of cellulase enzyme was discussed. In enzyme recovery by affinity method, The first recycling showed relatively high hydrolysis rate of 96.4%. Even at the third recycle, hydrolysis rate was 87.0 percents. In the case of cellulase recovery by ultrafiltration method, first 2 recycling treatments resulted in very high hydrolysis rates, 96.8% and 95.0%, respectively. Even the third recycling showed about 93.6%. Steam-explosion treatment of oak wood followed by 2-stage delignification with alkali and oxygen-alkali produced a excellant substrate for the enzymatic hydrolysis that allowed almost quantitative recycle of cellulase.

• Journal of the Korean Wood Science and Technology
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• v.45 no.2
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• pp.182-194
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• 2017

The optimum alkali pretreatment parameters (reaction time, reaction temperature and potassium hydroxide concentration) for facilitate the conversion into fermentable sugar (glucose) from steam exploded (severity log Ro 2.45) barley husk were determined using Response Surface Methodology (RSM) based on a factorial Central Composite Design (CCD). The prediction of the response was carried out by a second-order polynomial model and regression analysis revealed that more than 88% of the variation can be explained by the models. The optimum conditions for maximum cellulose content were determined to be 201 min reaction time, $124^{\circ}C$ reaction temperature and 0.9% potassium hydroxide concentration. This data shows that the actual value obtained was similar to the predicted value calculated from the model. The pretreated barley husk using acid hydrolysis resulted in a glucose conversion of 94.6%. This research of steam explosion and alkali pretreatment was a promising method to improve cellulose-rich residue for lignocellulosic biomass.

• Biomolecules & Therapeutics
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• v.12 no.3
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• pp.189-193
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• 2004

Over the past several years, research efforts have been directed both at economically producing valuable substances from the wood biomass and at producing lignolytic enzymes at a lower cost. In the present study, we found that Phellinus igniarius, the basidiomycetes, secreted lignin peroxidase as a main lignolytic enzyme, which was detected maximum activity at 16th day of culture and showed 37 kDa of molecular mass in identification by activity assay and purification by anion-exchange chromatography. The Phellinus igniarius-derived lignin peroxidase hydrolyzed steam-exploded wood (Quercus mongolica) powder into small molecules showing cytotoxicity against cancer cel1s (HepG2 hepatoma, SK-N-SH neuroblastoma, B16 melanoma, MBT-2 bladder cancer). In addition, the enzyme hydrlysates of lignins (ELg) that were extracted from the steam-exploded oak showed more potent cytotoxic effects on the cancer cells than the enzyme hydrolysates of wood biomass (EWp), indicating that the cytotoxic effect of EWp may be due to the enzyme-degraded products of lignin among the lignocellulosics. Furthermore, the cytotoxic effect of ELg on Chang, normal liver cells, was much less potent than that of ELg on HepG2 and B16 cancer cells, indicating that the cytotoxic effect of ELg may be specific for cancer cells. The present results suggest that Phellinus igniarius may be a useful resource for the large-scale production of lignin peroxidase and that the lignin peroxidase may be applied for the generation of valuable biodegradation products from wood lignocellulosics for medical use.

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.98-102
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• 2002

Lignocellulosic wastes available in abundance can be excellent substrates for the production of cellulase. Different types of substrates and various pretreatments were used to improve the production of cellulase. The steam-exploded wood chip gave the highest activities of FPase (0.84 IU/mL) and CMCase (6.5 IU/mL) in the shake-flask culture. In 30 L bioreactor the steam-exploded wood chip and residue after saccharification gave the FPase activity (0.72 IU/mL) and the CMCase activity (6.3 IU/mL), respectively, similar those obtained in lactose.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.53-60
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• 1993

Substrates used were hardwood-Suwon poplar-(Populus alba${\times}$glandulosa L.) and softwood-pitch pine-(Pinus rigida M.). And these substrates were steam exploded then treated with sodium chlorite at 75$^{\circ}C$ with occasional stirring in order to obtain samples which had different lignin contents and crystallinity. And then this resulting samples incubated with a commercial cellulase derived from Trichoderma ressei. The contents of Klason lignin were decreased as the increasing of the ratio of sodium chlorite in the two species. The effect of hardwood was more effective than that of softwood in the same ratio of sodium chlorite. The minimum contents of Klason lignin were 0.8% and 5.1% respectively. And the crystallinities of cellulose were increased very little as increasing of the ratio of sodium clorite. The hydrolysis extent of the two species were increased as the increasing of delignification. Especially, the hydrolysis extent of hardwood was more higher than that of softwood. The maximum hydrolysis extent were 89.8% and 71.1%, respectively.

• 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%.

• Journal of the Korean Wood Science and Technology
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• v.49 no.4
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• pp.384-393
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• 2021

Recently, due to environmental and toxicity issues, there has been increasing attention on research regarding natural products that can reduce the use of chemical fertilizers. Wood extracts derived from the biorefining process contain various fertilizer ingredients. HPLC analysis revealed that wood extract contains approximately 5.2% hemicellulosic sugar. The growth of lettuce (Lactuca sativa) upon treatment with wood extract (extract obtained from steam-exploded pine) or water-soluble fertilizers containing different nutrients was analyzed in this study. After two weeks, the growth characteristics of lettuce as affected by wood extract or water-soluble fertilizers were significantly different. The effect of water-soluble fertilizers containing ascorbic acid, magnesium sulfate, citric acid, potassium nitrate, amino acids, or seaweed extract was less desirable than that of wood extracts regarding plant height (18.6 cm), number of leaves (10), leaf length (14.1 cm), shoot fresh wight (9.8 g/plant), root fresh weight (0.8 g/plant) and shoot dry weight (0.6 g/plant). The plant height, number of leaves, leaf length, shoot fresh wight, root fresh weight, shoot dry weight of water-soluble fertilizers containing wood extract were significantly different compared to the control (plant height :13.5 cm, number of leaves : 7, leaf length : 9.4 cm, shoot fresh wight : 5.3 g/plant, root fresh weight : 0.7 g/plant, shoot dry weight : 0.4 g/plant, root dry weight : 0.07 g/plant). From these results, it was concluded that wood extract can be used as a potential water-soluble fertilizer to increase the yield of leafy vegetables.

• Journal of the Korean Wood Science and Technology
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• v.17 no.4
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• pp.57-69
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• 1989

Roughage feeds were produced from Hyun-aspen (Populus alba $\times$ p. glandulosa) by steaming-defibration and steaming-explosion. The objectives of this work were to find proper conditions for the treatment of Hyun-aspen by analyzing the compositional change and digestibility and to investigate the change of physical properties of exploded woods. The results of this work were as follows; 1. The method of steaming-de fibration gave the best producing rate of feedstuffs when the chips were steamed (9kg/$cm^2$ under the pressure) for 10 minutes. The yield and the digestibility of feedstuffs were 84.2% and 38.1%, respectively. It is the merit of this method that feedstuffs manufactured by this method was uniformity in particle size, and facilities of fiberboard factory could be used directly, 2. For defibration of the chip by explosion, the proper condition was steamed under the pressure (20kg/$cm^2$) for 4 minutes. The yield and the digestibility of feedstuffs were 93.4% and 68.1%, respectively. The feedstuffs produced under these conditions had higher nutritional quality than rice straw and this method was considered as the best for making feedstuffs from Hyun-aspen chip. But it is defect that exploded feedstuffs was ununiformity in particle size and had unique odor. The physical properties of the feedstuffs were investigated by a light microscope and a TEM. The feedstuffs produced under the low pressure (20 kg/$cm^2$) still maintained the structure of fibers. However, the feedstuffs produced under the high pressure (28 kg/$cm^2$) resulted in higher de fib ration than these prepared under the low pressure. The highly defibrated feedstuffs recombined with solublized lignin. The crystallinity of feedstuffs was increased by 10% and micelle width increased double after treatment.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.9-13
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• 2000

Wood demand is increasing more and more, but world has been confronted with decreasing forest resources. Korea has to depend upon foreign wood and wood-based products for more than 95 percent of total domestic demand per year. In order to heighten self-sufficiency for wood supply and demand, we have to develop wood substitutes. Rice hull is the cheapest agricultural by-product we can get in Korea, more over the production of rice hull amounts to 1 million tons per year. This study was carried out to utilize rice hull and to decide the optimum condition of rice hull pretreatment for manufacture of rice hull board. Steam explosion method gave the best result, and the next boiling treatment of 1 hour, the last 1 hour treatment with 1% NaOH solution. Optimum conditions of explosion method were 20kgf/$cm^2-1$ minute and 25kgf/$cm^2-1$ minute. Rice hull board made with exploded rice hull met the KS standard(KS F 3104, 1997) and showed the same strength as a control, PB. And also the 1 hour boiling treatment was more effective than the 1 hour treatment with 1% NaOH solution.

• Journal of the Korean Wood Science and Technology
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• v.40 no.2
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• pp.78-90
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• 2012

Soybean hull is an attractive feedstock for glucose production. To increase the glucose conversion in acid hydrolysis, a pretreatment method combined steam explosion with alkali pretreatment for soybean hull was studied. For first step pretreatment, steam explosion conditions (log Ro 2.45) were optimized to obtain maximum solid recovery and cellulose content. In the second step pretreatment, the conditions for potassium hydroxide pretreatment of steam exploded soybean hull were optimized by using RSM (response surface methodology). The optimum conditions for minimum lignin content were determined to be 0.6% potassium hydroxide concentration, $70^{\circ}C$ reaction temperature and 198 min reaction time. The predicted lignin content was 2.2% at the optimum conditions. Experimental verification of the optimum conditions gave the lignin content in similar value with the estimated value of the model. Finally, glucose conversion of pretreated soybean hull using acid hydrolysis resulted in $97.1{\pm}0.4%$. This research of two-step pretreatment was a promising method for increasing the glucose conversion in the cellulose-to-glucose process.