• Journal of Microbiology and Biotechnology
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• 제31권10호
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• pp.1438-1445
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• 2021

A bifunctional glycoside hydrolase GH78 from the ascomycete Xylaria polymorpha (XpoGH78) possesses catalytic versatility towards both glycosides and esters, which may be advantageous for the efficient degradation of the plant cell-wall complex that contains both diverse sugar residues and esterified structures. The contribution of XpoGH78 to the conversion of lignocellulosic materials without any chemical pretreatment to release the water-soluble aromatic fragments, carbohydrates, and methanol was studied. The disintegrating effect of enzymatic lignocellulose treatment can be significantly improved by using different kinds of hydrolases and phenoloxidases. The considerable changes in low (3 kDa), medium (30 kDa), and high (> 200 kDa) aromatic fragments were observed after the treatment with XpoGH78 alone or with this potent cocktail. Synergistic conversion of rape straw also resulted in a release of 17.3 mg of total carbohydrates (e.g., arabinose, galactose, glucose, mannose, xylose) per gram of substrate after incubating for 72 h. Moreover, the treatment of rape straw with XpoGH78 led to a marginal methanol release of approximately 17 ㎍/g and improved to 270 ㎍/g by cooperation with the above accessory enzymes. In the case of beech wood conversion, the combined catalysis by XpoGH78 and laccase caused an effect comparable with that of fungal strain X. polymorpha in woody cultures concerning the liberation of aromatic lignocellulose fragments.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.250-255
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• 2005

높은 원가인 펩톤을 다른 질소원으로 대체하기 위하여 콩 혹은 효모의 질소원 대체가능성을 검토한 결과 효모의 농도를 0.5%의 펩톤과 동등한 양의 질소원으로 하였을 때 amylase의 생산성이 2.30 U/ml로써 가장 높았다. 때문에 높은 원가의 펩톤을 효모로 대체하는 것이 가능할 것으로 사료된다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 추계학술발표회 논문집
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• pp.289-296
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• 2011

Recently, much of forest biomass has been obtained from the national forest management operation. Unfortunately, Korean Forest Services has a plan to use this forest biomass as energy fuels for wood pellets. Considering unhappy situation that about 80% of wood pulps has been imported, it is regarded as unwise decision. If forest biomass can be used to make pulps or other valuable woody products, we are able to double its economic value than the raw materials for wood pellets. In this study, we explored alternative raw materials for wood biomass used to make wood pellets. For this, fresh technology such as torrefaction was applied with the other lignocellulosic biomass.

• Journal of the Korean Wood Science and Technology
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• 제17권3호
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• pp.52-60
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• 1989

This study was carried out to know the possibility of simultaneous utilization of laccase from white-rot fungus with cellulase on enzymatic hydrolysis of cellulosic substrate from autohydrolyzed oak wood. Laccases from 3 white-rot fungi, Pleurotus ostreatus. Ganoderma lucidum, and Phanerochaete chrysosporium, were isolated, purified and measured their activities. The highest activity was shown in Pleurotus ostreatus and the lowest in Phanerochaete chrysosporium. Laccase from Pleurotus ostreatus has optimum pH of 5.94, Km value of 3.209 mM and appeared to be stable at relatively wide pH range, 4.7-8.72. Temperature stability showed that 60% activity was preserved after 40 minutes at $50^{\circ}C$. Laccase from Ganoderma lucidum reached to the maximum activity during 15-20 day incubation. This enzyme has optimum pH of 6.45, Km value of 6.71 mM and pH range of 5.0-9.0 for stabilization. 95% activity was preserved at $30^{\circ}C$ and 58% activity at $50^{\circ}C$. Concerned to the enzymatic hydrolysis of cellulosic substrate with both enzymes, cellulase and laccase, simultaneously, mixed culture filtrates and mycellium extracts were shown higher hydrolysis rates than those of Trichoderma viride. There were no significant differences in the extent of hydrolysis among various mixed culture filtrates and mycellium extracts.

• 한국미생물·생명공학회지
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• 제50권1호
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• pp.122-125
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• 2022

The cellulose-fed microbial fuel cell (MFC) is a biotechnological process that directly converts lignocellulosic materials to electricity without combustion. In this study, the cellulose-fed, MFC-integrated thermophilic bacterium, Bacillus sp. WK21, with endoglucanase and exoglucanase activities of 1.25 ± 0.08 U/ml and 0.95 ± 0.02 U/ml, respectively, was used to generate electricity at high temperatures. Maximal current densities of 485, 420, and 472 mA/m² were achieved when carboxymethyl cellulose, avicel cellulose, and cellulose powder, respectively, were used as substrates. Their respective maximal power was 94.09, 70.56, and 89.30 mW/m³. This study demonstrates the value of the novel use of a cellulase-producing thermophilic bacterium as a biocatalyst for electricity generation in a cellulose-fed MFC.

• Mycobiology
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• 제47권1호
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• pp.97-104
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• 2019

Mushroom cultivation has gained increased attention in recent years. Currently, only four types of spawn, including sawdust spawn, grain spawn, liquid spawn, and stick spawn, are commonly available for mushroom cultivation. This limited spawn diversity has led to difficulty in selecting suitable inoculum materials in some cultivation. In this study, three small blocks of lignocellulosic agro-wastes and one block of a synthetic matrix were prepared as support for growing Pleurotus ostreatus in liquid medium. Mycelium-adsorbed blocks were then evaluated for their potential as block spawn for fructification. Our results indicated that the edible fungus was adsorbed and abundantly grew internally and externally on loofah sponge and synthetic polyurethane foam (PUF) supports and also has the ability to attach and grow on the surface of sugarcane bagasse and corncob supports. The mycelia of P. ostreatus adhered on corncob exhibited the highest metabolic activity, while those on the PUF showed the least activity. Mycelial extension rates of block spawns made of agro-waste materials were comparable to that of sawdust spawn, but the block spawn of PUF showed a significantly lower rate. No significant differences in cropping time and yield were observed among cultivations between experimental block spawns and sawdust spawns. Moreover, the corncob block spawn maintained its fruiting potential during an examined period of 6-month storage. The developed block spawn could be practically applied in mushroom cultivation.

• Mycobiology
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• 제43권1호
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• pp.57-62
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• 2015

${\beta}$-Glucosidase, which hydrolyzes cellobiose into two glucoses, plays an important role in the process of saccharification of the lignocellulosic biomass. In this study, we optimized the activity of ${\beta}$-glucosidase of brown-rot fungus Fomitopsis pinicola KCTC 6208 using the response surface methodology (RSM) with various concentrations of glucose, yeast extract and ascorbic acid, which are the most significant nutrients for activity of ${\beta}$-glucosidase. The highest activity of ${\beta}$-glucosidase was achieved 3.02% of glucose, 4.35% of yeast extract, and 7.41% ascorbic acid where ascorbic acid was most effective. The maximum activity of ${\beta}$-glucosidase predicted by the RSM was 15.34 U/mg, which was similar to the experimental value 14.90 U/mg at the 16th day of incubation. This optimized activity of ${\beta}$-glucosidase was 23.6 times higher than the preliminary activity value, 0.63 U/mg, and was also much higher than previous values reported in other fungi strains. Therefore, a simplified medium supplemented with a cheap vitamin source, such as ascorbic acid, could be a cost effective mean of increasing ${\beta}$-glucosidase activity.

• 펄프종이기술
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• 제48권2호
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• pp.34-45
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• 2016

Global warming and climate change have been caused by combustion of fossil fuels. The greenhouse gases contributed to the rise of temperature between $0.6^{\circ}C$ and $0.9^{\circ}C$ over the past century. Presently, fossil fuels account for about 88% of the commercial energy sources used. In developing countries, fossil fuels are a very attractive energy source because they are available and relatively inexpensive. The environmental problems with fossil fuels have been aggravating stress from already existing factors including acid deposition, urban air pollution, and climate change. In order to control greenhouse gas emissions, particularly CO2, fossil fuels must be replaced by eco-friendly fuels such as biomass. The use of renewable energy sources is becoming increasingly necessary. The biomass resources are the most common form of renewable energy. The conversion of biomass into energy can be achieved in a number of ways. The most common form of converted biomass is pellet fuels as biofuels made from compressed organic matter or biomass. Pellets from lignocellulosic biomass has compared to conventional fuels with a relatively low bulk and energy density and a low degree of homogeneity. Thermal pretreatment technology like torrefaction is applied to improve fuel efficiency of lignocellulosic biomass, i.e., less moisture and oxygen in the product, preferrable grinding properties, storage properties, etc.. During torrefacton, lignocelluosic biomass such as palm kernell shell (PKS) and empty fruit bunch (EFB) was roasted under an oxygen-depleted enviroment at temperature between 200 and $300^{\circ}C$. Low degree of thermal treatment led to the removal of moisture and low molecular volatile matters with low O/C and H/C elemental ratios. The mechanical characteristics of torrefied biomass have also been altered to a brittle and partly hydrophobic materials. Unfortunately, it was much harder to form pellets from torrefied PKS and EFB due to thermal degradation of lignin as a natural binder during torrefaction compared to non-torrefied ones. For easy pelletization of biomass with torrefaction, pellets from PKS and EFB were manufactured before torrefaction, and thereafter they were torrefied at different temperature. Even after torrefaction of pellets from PKS and EFB, their appearance was well preserved with better fuel efficiency than non-torrefied ones. The physical properties of the torrefied pellets largely depended on the torrefaction condition such as reaction time and reaction temperature. Temperature over $250^{\circ}C$ during torrefaction gave a significant impact on the fuel properties of the pellets. In particular, torrefied EFB pellets displayed much faster development of the fuel properties than did torrefied PKS pellets. During torrefaction, extensive carbonization with the increase of fixed carbons, the behavior of thermal degradation of torrefied biomass became significantly different according to the increase of torrefaction temperature. In conclusion, pelletization of PKS and EFB before torrefaction made it much easier to proceed with torrefaction of pellets from PKS and EFB, leading to excellent eco-friendly fuels.

• Journal of the Korean Wood Science and Technology
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• 제45권4호
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• pp.432-443
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• 2017

Maltodextrin and citric acid are two types of natural materials with the potential as an eco-friendly binder. Maltodextrin is a natural substance rich in hydroxyl groups and can form hydrogen bonds with lignoselulosic material, while citric acid is a polycarboxylic acid which can form an ester bond with a hydroxyl group at lignoselulosic material. The combination of maltodextrin and citric acid as a natural binder materials supposed to be increase the ester bonds formed within the particleboard. This research determined to investigate the bonding properties of a new adhesive composed of maltodextrin/citric acid for nipa frond particleboard. Maltodextrin and citric acid were dissolved in distillated water at the ratios of 100/0, 87.5/12.5, 75/25 and 0/100, and the concentration of the solution was adjusted to 50% for maltodextrin and 60% citric acid (wt%). This adhesive solution was sprayed onto the particles at 20% resin content based on the weight of oven dried particles. Particleboards with a size of $25{\times}25{\times}1cm$, a target density $800kg/m^3$ were prepared by hot-pressing at press temperatures of $180^{\circ}C$ or $200^{\circ}C$, a press time of 10 minute and board pressure 3.6 MPa. Physical and mechanical properties of particleboard were tested by a standard method (JIS A 5908). The results showed that added citric acid level in maltodextrin/citric acid composition and hot-pressing temperature had affected to the properties of particleboard. The optimum properties of the board were achieved at a pressing temperature of $180^{\circ}C$ and the addition of only 20% citric acid. The results also indicated that the peak intensity of C=O group increased and OH group decreased with the addition of citric acid and an increase in the pressing temperature, suggesting an interreaction between the hydroxyl groups from the lignocellulosic materials and carboxyl groups from citric acid to form the ester groups.

• 펄프종이기술
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• 제45권1호
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• pp.13-20
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• 2013

In this study, oil palm biomass such as empty fruit bunch (EFP) and palm kernel shell (PKS) was used as raw materials for making pellets. EFB and PKS are valuable lignocellulosic biomass that can be used for various purposes. If EFB and PKS are used as alternative raw materials for making pellets instead of wood, wood could be saved for making pulps or other value-added products. In order to explore their combustion characteristics, EFB and PKS were analyzed using thermal gravimetric analyzer (TGA) with ultimate and proximate analyses. From the TGA results, thermal decomposition of EFB and PKS occurred in the range of 280 to $400^{\circ}C$ through devolatilization and combustion of fixed carbon. After $400^{\circ}C$, their combustion were stabilized with combustion of residual lignin and char. PKS contained more fixed carbons and less ash contents than EFB, which indicated that PKS could be more active in combustion than EFB.