Monitoring the cell wall characteristics of degraded beech wood by white-rot fungi: Anatomical, chemical, and photochemical study

Meticulous chemical analysis of decaying xylem and linking it to corresponding anatomical modification at the cellular level can improve our understanding of the decay process. The aim of this study was to monitor the histological, chemical, photochemical, and progression of wood degradation by two white-rot fungi at different intervals. Oriental beech wood (Fagus orientalis) blocks were exposed to Pleurotus ostreatus and Trametes versicolor to investigate the degradation capabilities of these two fungi. Light microscopy was used to study the decay patterns in wood. Decayed wood samples were also analyzed to determine lignin, cellulose and sugar contents and also evaluated at two week intervals by FT-IR spectroscopy to study chemical alterations. According to chemical analyses lignin is the most degraded polymer followed by cellulose and hemicelluloses for both white rot fungi. However, both test fungi tended to consume lignin more than cellulose. FT-IR spectra changes for  lignin and carbohydrates in beech wood supported chemical alteration and indicated that both fungi decay wood in a simultaneous pattern.&nbsp

Heat Modification of Wood: Chemical Properties and Resistance to Mold and Decay Fungi

The resistance of heat modified sugi (Crvptomeria japonica D) sapwood against mold and decay fungi was evaluated under laboratory conditions Wood specimens were subjected to heat treatment at 180 C for 2 and 4 hours and at 220 C for 2 hours Changes in lignin and polysaccharide weight percent composition, solubility, and pH of heat-modified specimens were determined Treatment at 220 C for 2 hours decreased wood polysaccharide content Heat treatment slightly increased resistance against Rhizopus javanicus and Gliocladium (Trichoderma) wrens but not against Aspergillus rage, The highest temperature used increased resistance to decay by the white-rot fungus Trametes versicolor but mass losses with the brown-rot fungus Fomitopsis palustris were higher than those with T versicolo

Heat Modification of Wood: Chemical Properties and Resistance to Mold and Decay Fungi

The resistance of heat modified sugi (Crvptomeria japonica D) sapwood against mold and decay fungi was evaluated under laboratory conditions Wood specimens were subjected to heat treatment at 180 C for 2 and 4 hours and at 220 C for 2 hours Changes in lignin and polysaccharide weight percent composition, solubility, and pH of heat-modified specimens were determined Treatment at 220 C for 2 hours decreased wood polysaccharide content Heat treatment slightly increased resistance against Rhizopus javanicus and Gliocladium (Trichoderma) wrens but not against Aspergillus rage, The highest temperature used increased resistance to decay by the white-rot fungus Trametes versicolor but mass losses with the brown-rot fungus Fomitopsis palustris were higher than those with T versicolo

Some properties of kraft and kraft-borate pulps of different wood species

Comparative analyses were carried out on the properties of birch, maple, and spruce for conventional kraft pulping and kraft pulping with sodium metaborate added to correspond to 35 % autocausticizing. A 1.8 % increase was noticed in the screened yield for the kraft-borate pulping of spruce at H-factors higher than 1000. Also, at kappa numbers lower than 50, sodium metaborate increased the total yield in spruce pulping. Sodium borate did not affect the brightness nor the contents of extractives and hexenuronic acid groups (HexA) of the kraft pulps for the species studied. The kappa number corrected for the HexA component, which is a more accurate estimate of the lignin content, showed that kraft delignification was not changed by sodium metaborate at the increasing H-factor. An increase of holocellulose retention was found for the kraft-borate pulps of spruce at the kappa numbers lower than 60, indicating that sodium metaborate has the potential to protect carbohydrates in kraft pulping

Comparative studies of kraft and kraft-borate pulping of black spruce

Borate autocausticizing can either replace (total autocausticizing) or supplement the kraft lime cycle (partial autocausticizing). Partial autocausticizing has been recently commercialized in one kraft mill and is undergoing trials in several additional mills. Although it is known that borate reacts with lignin, little information is available on the effect of borates on kraft pulp yield or fibre properties. The objectives of this study were to determine the effect of sodium metaborate, which is the borate product from autocausticizing, on kraft pulping and on the properties of black spruce pulps. The major findings of this study suggest that borate increases yield, can decrease rejects, improves the selectivity of lignin removal, does not affect the delignification rate and can increase pulp viscosity at the same kappa number

Physical, mechanical, and chemical properties of steamed beech wood

Steam treatment is often applied to beech (Fagus orientalis Lipsky) to improve the stability and permeability of the wood, obtain a desirable color, and soften the wood. This paper evaluates the effect of steaming on the physical, mechanical, and chemical characteristics of beech steamed for 20,50,70, and 100 hours at 80 degreesC. The results show that steaming decreases the strength and physical properties of the wood. Following 100 hours of steaming, compression strength and modulus of elasticity decreased 13.2 and 16.5 percent, respectively. Steaming had a slight effect on radial and tangential shrinkage, and reduced density about 2 percent. Hemicelluloses in steamed wood decreased only 7 to 9 percent, but wood solubility was greatly decreased. Acetyl content also decreased with steaming as hemicelluloses decreased. The lignin content of steamed wood was slightly higher than that of untreated wood

Role of various nano-particles in prevention of fungal decay, mold growth and termite attack. in wood, and their effect on weathering properties and water repellency

The resistance of Scots pine wood vacuum-treated with nano-particles of ZnO, B2O3, CuO, TiO2, CeO2, and SnO2 against decay, mold fungi and subterranean termites was evaluated. Weathering and water absorption properties were also studied. Nano-ZnO only was resistant against leaching, while the other compounds leached out from wood specimens at more than 60% release rates. Mold growth in wood specimens was significantly inhibited by treatment with nano-ZnO and nano-B2O3. In Petri dishes, all mold fungi were also inhibited by nano-ZnO and nano-B2O3; however, nano-SnO2 inhibited Trichoderma harzianum growth only. Weight loss from fungal attack by the brown-rot fungus was significantly inhibited by all nano-compounds tested, except for leached specimens of nano-B2O3 treatments. Considerably higher weight losses were obtained in decay resistance tests by the white rot fungus; only nano-CuO and nano-SnO2 were effective against this fungus. Nano-CuO and nano B2O3 treatments produced favorable termite resistance in both weathered and unweathered specimens, while nano-ZnO and nano-CeO2 resulted in decreased weight loss in specimens exposed to termites. Nano-ZnO was slightly effective in decreasing water absorption. Exposing untreated wood specimens to artificial weathering resulted in significant changes in the chemical structure as determined by FT-IR analysis; however, weathering effect was somewhat decreased by the incorporation of the nano-compounds. (C) 2015 Elsevier Ltd. All rights reserved

Evaluation of Fungal Deterioration in Liquidambar orientalis Mill. Heartwood by FT-IR and Light Microscopy

The chemical and morphological changes in heartwood specimens of Liquidambar orientalis Mill. caused by the white-rot fungus Trametes versicolor and the brown-rot fungi Tyromyces palustris and Gloeophyllum trabeum were studied by wet chemistry, FT-IR, GC-MS analyses, and photo-microscopy. According to GC-MS results, 26 extracts identified in the ethanol/toluene extraction and 17 in the ethanol extraction were found. Heartwood specimens of L. orientalis were highly susceptible to the fungi tested. While 1% NaOH solubility increased 35% in the specimen decayed by T. palustris, only an 8% increase was seen in the specimen exposed to T. versicolor when compared to the control specimen. Decayed wood by T. palustris showed a 5.5% increase in the Klason lignin content when compared to control specimens; however, the Klason lignin content decreased after a T. versicolor attack for 12 weeks. A T. versicolor attack in the cell walls was seen both from the lumina and from the cell corners, and the attack from the cell corners was mainly clear in ray parenchyma cells. An excessive destruction was detected in the wood structure attacked by T. palustris. The cell collapse was caused by a distortion in the plane of the wood cells. This extensive degradation was seen in all types of cell walls. Cracks in the cell walls were also detected in the specimens