• Journal of the Korean Wood Science and Technology
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• v.46 no.4
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• pp.415-422
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• 2018

Terpenoids have a wide range of biological functions and have extensive applications in the pharmaceutical, cosmetic, and flavoring industry. The white-rot fungus, Polyporus brumalis, is able to synthesize terpenoids via terpene synthase, which catalyzes an important step that forms a large variety of sesquiterpene products from farnesyl pyrophosphate (FPP). To improve the production of sesquiterpenes, the terpene synthase gene was isolated from Polyporus brumalis and was heterologously transformed into a Pichia pastoris strain. The open reading frame of the isolated gene (approximately 1.2 kb) was inserted into Pichia pastoris to obtain a recombinant enzyme. Five transformants were obtained and the expression of terpene synthase was analyzed at the transcript level by reverse transcription PCR (polymerase chain reaction) and at the protein level by SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis). Expression of the terpene synthase gene product was elevated in the transformants and as expected the molecular weight of the protein was approximately 45 kDa. These recombinant enzymes have potential practical applications and future studies should focus on their functional characterization.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.3
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• pp.223-228
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• 2004

Agricultural waste products, beech wood and walnut shells, were hydrolyzed at 40$^{\circ}C$ using mixed crude enzymes produced by Penicillium sp. AHT-1 and Rhizomucor pusillus HHT-1. D-xylose, 4.1 g and 15.1 g was produced from the hydrolysis of 100 g of beech wood and walnut shells, respectively. For xylitol production, Candida tropicalis IFO0618 and the waste product hydrolyzed solutions were used. The effects on xylitol production, of adding glucose as a NADPH source, D-xylose and yeast extract, were examined. Finally, a 50% yield of xylitol was obtained by using the beech wood hydrolyzed solution with the addition of 1% yeast extract and 1% glucose at an initial concentration.

• Journal of the Korean Wood Science and Technology
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• v.41 no.4
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• pp.293-301
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• 2013

This study discusses the feasibility of coffee bean residue as a raw material of medium-density fiberboard (MDF). In this relation, the effect of coffee bean residue known as an absorbent material on the physical and mechanical properties of MDF manufactured at its different addition level. Coffee bean residue which is a by-product of coffee mill and large amount of waste left over after processing for instant coffee was added at the level of 3, 6, and 9% on dry basis and urea formaldehyde resin was used as the adhesive. The MDF made with mixture of wood fiber and coffee bean residue was tested for physical and mechanical properties as well as formaldehyde emission. The bending strength and internal bonding strength of the MDF made with mixture of wood fiber-coffee bean residue were higher than that of the KS standard in randomized mat structure type, but not in layered mat structure type. Also, the physical properties of MDF made with mixture of wood fiber-coffee bean residue showed a considerable improvement in thickness swelling over the commercial MDF. More importantly, the formaldehyde emission rate of MDF made with mixture of wood fiber-coffee bean residue met the KS standard and was close to that of commercial MDF. These results showed the feasibility of coffee bean residue as a raw material for the production of environmentally-friendly MDF. Additional works on adhesive-coffee bean compatibility, improvement of moisture absorption effect and reduction the formaldehyde emission rate by carbonization of coffee bean residue may be required.

• Journal of the Korean Wood Science and Technology
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• v.34 no.1
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• pp.52-60
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• 2006

This study investigated how wood properties (i.e., annual rings, sapwood, heartwood, and cracks) might affect preservative treatment in Japanese larch (Larix leptolepis) round-wood product. We specially focused on small-diameter (~10 cm diameter) wood that is commercially sold in market. Among 100 wood samples, the groups of sample with 13~16, 17~20 annual rings represented 33 and 27 in each frequency, while 2~3 and 4~5 mm annual ring width accounted for 72 and 68 in frequency. More than a half (54%) of wood samples contained a mix of heartwood and sapwood in its surface. The rest (46%) had only heartwood exposed in the wood surface. A wide range of checks were showed in the wood samples, but the highest frequency was observed in samples with 1~6 surface (1~14 mm in size) checks and 1~4 end-grain (8~14 mm in size) checks in each round-wood sample. Pressure treatment resulted in a wide range of penetration of ACQ (Alkaline Copper Quat) into the wood, showing $4.3{\pm}4.19mm$ penetration in the wood samples contained a mix of heartwood and sapwood in its surface. However preservative treatment was much less effective for the heartwood only wood samples, ranging average 1.3 mm with ACQ and 1.1 mm with CCA (Chromated Copper Arsenate). These penetration results shown in heartwood samples did not meet the penetration standard that is required for H3 by the Korean Forest Service in relation to wood preservation treatment. These low penetration results were not significantly improved even if we incised wood samples to improve treatment effect, showing only small increase of 0.7 mm with ACQ and 0.6 mm with CCA. When preservative treatment was tested with heartwood, penetration of preservatives decrease with increase of annual rings per a cross-section area (r=0.5345). We also found that the length and number of check had no effect on preservative treatment, showing r=0.1301 and r=0.1802, respectively.

• Journal of the Korean Wood Science and Technology
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• v.52 no.4
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• pp.343-362
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• 2024

Eurycoma longifolia (pasak bumi) is a popular medicinal plant in Indonesia and is widely used in various products. Its high economic value has caused illegal harvesting and product falsification. Using molecular techniques, the authentication and traceability of E. longifolia derivatives can be controlled to ensure consumer safety. Therefore, this study aimed to authenticate the products and derivatives of E. longifolia (pasak bumi) produced, marketed, and consumed in Indonesia using molecular identification techniques. Genomic DNA from 37 leaf samples collected from the Sumatran mainland and the Riau Islands and six E. longifolia products were amplified and sequenced using trnL-trnF and internal transcribed spacer (ITS) regions. The results revealed that all leaf samples were indeed E. longifolia based on the markers used, with the six products, only the herbal tea product (sample code TCPB) was most likely derived from E. longifolia based on the two regions, suggesting that not all products labelled as E. longifolia in the market are authentic. The results also indicated that several other plants species are used as substitutes or adulterants, including Simaba spp., Simarouba spp., Homalolepis spp., Vernonia gigantea, Elephantopus scaber, Gymnanthemum amygdalinum, Cyanthillium spp., Potentilla lineata, Ailanthus altissima, Geijera paniculata, Hannoa chlorantha, and Dalbergia spp. Klebsiella pneumoniae bacteria were also identified in this study on the outer wooden cup of E. longifolia products. Therefore, this molecular approach is effective in identifying the authenticity of E. longifolia products, with trnL-trnF and ITS as the recommended DNA markers.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.907-916
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• 2020

This research was conducted to investigate the linear expansion and resistance properties of a composite board (com-ply). This board was made of medium-density fiberboard (MDF) laminated using avocado (Persea americana), mahogany (Swietenia mahogani), and pine (Pinus merkusii) veneers. These three types of veneers were laminated on both surfaces of the MDF using adhesives, namely, epoxy and isocyanate. Glue (250 g·m^-2) was spread on the surface, followed by cold press for 3 h with an applied pressure of 15 kg·cm^-2. The research result revealed that com-ply exhibited an increased dimensional stability compared with MDF, indicated by reduction in water absorption, thickness swelling, and linear expansion. The com-ply made of the pine veneer and isocyanate adhesive exhibited high density, water absorption, thickness swelling, and screw withdrawal load. The com-ply that exhibited the strongest resistance to drywood termite attacks was the one made of the mahogany veneer and isocyanate adhesive. Moreover, the com-ply that exhibited the biggest weight loss (3.6 %) was made of the pine veneer and epoxy adhesive. The results of this research may facilitate in manufacturing com-ply using the selected veneer and adhesive without the application of hot press.

• Journal of the Korean Wood Science and Technology
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• v.32 no.5
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• pp.59-65
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• 2004

The present study aims to optimise the process parameters of fish glue and adhesion property through room temperature in terms of curing time and opened assembly time for attaining best adhesion strength to wood (Yellow birch, B. alleghaniensis). The uncured and cured fish glue have been characterised by TGA, DSC, FT-JR. It is observed that with increasing curing time up to 48 H, tensile lap shear strength of adhesive joint of fish glue to wood increases and decreases after 48 H. At 15 min. opened assembly time, lap shear strength increases up to 4833 kgf/cm² and decreases after 15 min.

• Journal of the Korean Wood Science and Technology
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• v.15 no.4
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• pp.26-31
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• 1987

The ultraviolet and infrared spectra of dioxane lignin from bamboo were investigated. 1. Spectrum curve type considerably resembled that of wood lignin. There were 3 absorption peak positions at 210nm(max. peak), at 260-270nm(shallow mini. peak), at 280nm(lower max. peak) as in the wood lignin spectra. 2. The lower minimum peak near at 280 nm is the typical peak of lignin. This peak does not exist exactly at 280 nm but from 282nm to 285nm in this bamboo UV spectra. The absorption intensities are equal in this region and the peak is not sharp. 3. The absorption band of aromatic nucleus is near at wave number $1550cm^{-1}$ in the IR spectra of bamboo lignin. The intensity at about 1040-$1130cm^{-1}$ and at about 1230-$1275cm^{-1}$ were similar in the hardwood lignin but reverse to that of softwood lignin spectrum.

• Journal of the Korean Wood Science and Technology
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• v.50 no.2
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• pp.93-103
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• 2022

Currently, biofibers are used as a reinforcement in polymer composites for structural elements and construction materials instead of the synthetic fibers which cause environmental problems and are expensive. One of the chemicals with a pH close to neutral that can be potentially used as a modified fiber material is sodium chloride (NaCl). Therefore, this study aims to investigate the characteristics of a composite board made from NaCl-treated kenaf fiber. A completely randomized design method was used with consideration of two factors: the content of NaCl in the treatment solution (1 wt%, 3 wt%, and 5 wt%) and the duration of immersion of fibers in the solution (1 h, 2 h, and 3 h). The NaCl treatment was conducted by soaking the fibers in the solution for different durations. The fibers were then rinsed with water until the pH of the water reached 7 and subsequently dried inside an oven at 80℃ for 6 h. Kenaf fiber and epoxy were mixed manually with the total loading of 20 wt% based on the dry weight of the fiber. Physical and mechanical properties of the fibers were then evaluated based on JIS A 5908 particleboard standards. The results showed that increasing NaCl content in the fiber treatment solution can increase the physical and mechanical properties of the composite board. The properties of fibers treated with 5 wt% NaCl for 3 h were superior with a modulus of elasticity of 2.085 GPa, modulus of rupture of 19.77 MPa, internal bonding of 1.8 MPa, thickness swelling of 3%, and water absorption of 10.9%. The contact angle of untreated kenaf fibers was 104°, which increased to 80° and 73° on treatment with 1 wt% and 5 wt% NaCl for 3 h, respectively.

• Journal of the Korean Wood Science and Technology
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• v.51 no.5
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• pp.334-344
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• 2023

Dregs from the sugar palm (Arenga pinnata) starch industry are considered a waste product of the agricultural industry and have not yet been optimally utilized. Therefore, this study aimed to manufacture particleboards from dregs using different amounts of adhesive and particle size ratios. Sugar palm dregs, which had been separated into fibers and powder/fine particles, were used as raw material for making particleboards. The fiber had an average length of 6.84 ± 3.23 cm, while the fine particles were of a size that passed through size 10 mesh and remained in size 60 mesh. Three ratios of fiber to fine particles (100:0, 75:25, and 50:50 wt%) with three different amounts of sucrose-citric acid adhesive (10, 15, and 20 wt%) were used in this study. Increasing the amount of fine particles and the resin content can improve the physical properties and the internal bond strength of boards made from sugar palm dregs. The fine particles possibly filled the gap between the fibers in the particleboard, while the fibers exhibited a high bending strength. As a result, a high-performance particleboard can be attained by combining the composition ratio of fiber/fine particles and resin content. In this study, particleboards made from fiber/fine particles (75:25 wt%) and adhesive content of 15 wt% and 20 wt% had the mechanical properties that met the requirements of Japanese Industrial Standard (JIS) A 5908 type 18. Sugar palm dregs have the potential to be used as raw materials to create value-added particleboards.