Mode of action of brown rot decay resistance of thermally modified wood: resistance to Fenton’s reagent

Abstract The resistance of heat treated (HT) wood to brown rot fungi has been investigated, while the role of the Fenton reaction (FR) in the initial phase of degradation was in focus. Micro-veneers made of Scots pine, were HT with various intensities and their mass losses (MLHT) were determined before soaking with a solution of Fenton’s reagent containing Fe ions and hydrogen peroxide. The mass loss of the veneers treated that way (MLFT), their tensile strength loss (TSLFT) and the H2O2 decomposition were observed. The MLFT, TSLFT, and H2O2 loss decreased with increasing MLHT of the veneers. Soaking of the veneers in acetate buffer containing only Fe without H2O2 revealed that the heat treatment (HT) strongly reduces the Fe uptake by the cell walls. FTIR spectroscopy indicated oxidation of the unmodified control veneers but did not reveal predominant decay of cell wall components; the HT veneers were not changed at all due to FR. It was concluded that the reason for the enhanced resistance of HT wood to FR is attributable to hindered diffusion of Fe ions into the wood cell wall.

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Mode of action of brown rot decay resistance of acetylated wood: resistance to Fenton’s reagent

Wood Science and Technology ◽

10.1007/s00226-015-0790-0 ◽

2015 ◽

Vol 50 (2) ◽

pp. 413-426 ◽

Cited By ~ 11

Author(s):

Reza Hosseinpourpia ◽

Carsten Mai

Keyword(s):

Mode Of Action ◽

Brown Rot ◽

Decay Resistance ◽

Fenton’S Reagent ◽

Fenton's Reagent ◽

Brown Rot Decay ◽

Wood Resistance

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Mode of action of brown rot decay resistance in phenol-formaldehyde-modified wood: resistance to Fenton’s reagent

Holzforschung ◽

10.1515/hf-2015-0045 ◽

2016 ◽

Vol 70 (3) ◽

pp. 253-259 ◽

Cited By ~ 8

Author(s):

Reza Hosseinpourpia ◽

Carsten Mai

Keyword(s):

Cell Wall ◽

Mode Of Action ◽

Fenton Reaction ◽

Phenol Formaldehyde ◽

Brown Rot ◽

Weight Percent ◽

Fenton’S Reagent ◽

Fenton's Reagent ◽

Brown Rot Decay ◽

Modified Wood

Abstract The mode of action of phenol-formaldehyde (PF)-modified wood has been investigated with respect to its resistance to brown rot decay. The Fenton reaction is assumed to play a key role in the initial brown rot decay. Pine microveneers were modified to various weight percent gains (WPG) with low molecular weight PF and exposed to a solution containing Fenton’s reagent. The mass loss (ML) and tensile strength loss (TSL) as well as the decomposition of hydrogen peroxide within the incubation time decreased with the increasing WPG of the veneers. Incubation of untreated and PF-modified veneers in acetate buffer containing ferric ions without H2O2 revealed that the modification strongly reduces the uptake of iron by the wood cell wall. Further studies indicated that lignin promotes the decay of wood by Fenton’s reagent. The reason for the enhanced resistance of modified wood to the Fenton reaction is attributable to the impeded diffusion of iron ions into the cell wall rather than to the blocking of free phenolic sites of lignin, which accelerate redox cycling of iron.

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Mode of action of brown rot decay resistance in modified wood: a review

Holzforschung ◽

10.1515/hf-2013-0057 ◽

2014 ◽

Vol 68 (2) ◽

pp. 239-246 ◽

Cited By ~ 66

Author(s):

Rebecka Ringman ◽

Annica Pilgård ◽

Christian Brischke ◽

Klaus Richter

Keyword(s):

Cell Wall ◽

Mode Of Action ◽

Wood Decay ◽

Brown Rot ◽

Decay Resistance ◽

Hydroxyl Groups ◽

Decay Fungi ◽

Brown Rot Decay ◽

Thermally Modified Wood ◽

Modified Wood

Abstract Chemically or physically modified wood materials have enhanced resistance to wood decay fungi. In contrast to treatments with traditional wood preservatives, where the resistance is caused mainly by the toxicity of the chemicals added, little is known about the mode of action of nontoxic wood modification methods. This study reviews established theories related to resistance in acetylated, furfurylated, dimethylol dihydroxyethyleneurea-treated, and thermally modified wood. The main conclusion is that only one theory provides a consistent explanation for the initial inhibition of brown rot degradation in modified wood, that is, moisture exclusion via the reduction of cell wall voids. Other proposed mechanisms, such as enzyme nonrecognition, micropore blocking, and reducing the number of free hydroxyl groups, may reduce the degradation rate when cell wall water uptake is no longer impeded.

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Protection mechanisms of DMDHEU treated wood against white and brown rot fungi

Holzforschung ◽

10.1515/hf.2009.051 ◽

2009 ◽

Vol 63 (3) ◽

Cited By ~ 30

Author(s):

Pradeep Verma ◽

Ulrich Junga ◽

Holger Militz ◽

Carsten Mai

Keyword(s):

Cell Wall ◽

Treated Wood ◽

Weight Percent Gain ◽

Brown Rot ◽

Weight Percent ◽

Decay Resistance ◽

Brown Rot Fungi ◽

Protection Mechanisms ◽

Mesh Bags ◽

Fine Wood

AbstractThe resistance of beech and pine wood blocks treated with 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU) againstTrametes versicolorandConiophora puteanaincreased with increasing weight percent gain (WPG) of DMDHEU. Full protection [mass loss (ML) below 3%] was reached at WPGs of approximately 15% (beech) and 10% (pine). Untreated and DMDHEU treated blocks were infiltrated with nutrients and thiamine prior to fungal incubation and it was observed whether the destruction or removal of nutrients and vitamins during the modification process has an influence on the ML caused by the fungi. This study revealed that no considerable differences were found. Then, the cell wall integrity was partly destroyed by milling and the decay of the fine wood powder filled into steel mesh bags was compared to that of wood mini-blocks. The purpose of this study was to examine whether the effects of surface area, cell wall bulking, and reduction in micro-void diameters play a role in decay resistance. The ML caused by the fungi, however, also decreased with increasing WPG and showed comparable patterns similar to the case of mini-blocks. ML of powder bearing the highest WPG appeared to be caused by losses in DMDHEU during fungal incubation. For brown rotted wood, the infrared absorption ratios at 1030 cm-1and 1505 cm-1revealed decreasing decay of polysaccharides with increasing WPG of treated wood.

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Colour of larch heartwood and relationships to extractives and brown-rot decay resistance

Trees ◽

10.1007/s00468-003-0290-y ◽

2004 ◽

Vol 18 (1) ◽

pp. 102-108 ◽

Cited By ~ 75

Author(s):

Notburga Gierlinger ◽

Dominique Jacques ◽

Michael Grabner ◽

Rupert Wimmer ◽

Manfred Schwanninger ◽

...

Keyword(s):

Brown Rot ◽

Decay Resistance ◽

Brown Rot Decay

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Myofibrillar cell wall extensions in the hyphal sheath of Postia placenta

Canadian Journal of Microbiology ◽

10.1139/m92-147 ◽

1992 ◽

Vol 38 (9) ◽

pp. 905-911 ◽

Cited By ~ 9

Author(s):

Michael J. Larsen ◽

Frederick Green III

Keyword(s):

Cell Wall ◽

Brown Rot ◽

Decay Process ◽

Structural Components ◽

Hyphal Cell ◽

Postia Placenta ◽

Glass Cover ◽

Hyphal Sheath ◽

Brown Rot Decay ◽

Extracellular Structures

Evidence is provided for the existence of linear extracellular fibrillar elements in the brown-rot fungus Postia placenta. These elements appear as structural components of the hyphal sheath and more closely resemble mycofibrils than fungal fimbriae. Mycofibrils are associated with and appear to originate from the hyphal surface when hyphae are grown on wood or inert substrates, such as glass cover slips and polycarbonate filters. These extracellular structures have a nominal diameter of 10–50 nm and are up to 25 μm in length. We conclude that mycofibrils are linear structural extensions of the hyphal cell wall. The precise function of mycofibrils in the brown-rot decay process of wood remains to be elucidated. Key words: Postia placenta, mycofibrils, fungal fimbriae, hyphal sheath, electron microscopy.

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Resistance of thermally modified and pressurized hot water extracted Scots pine sapwood against decay by the brown-rot fungus Rhodonia placenta

European Journal of Wood and Wood Products ◽

10.1007/s00107-019-01482-z ◽

2019 ◽

Vol 78 (1) ◽

pp. 161-171 ◽

Cited By ~ 5

Author(s):

Michael Altgen ◽

Suvi Kyyrö ◽

Olli Paajanen ◽

Lauri Rautkari

Keyword(s):

Cell Wall ◽

Mass Loss ◽

Scots Pine ◽

Elevated Temperatures ◽

Brown Rot ◽

Decay Resistance ◽

Hot Water ◽

Decay Fungi ◽

Effective Reduction ◽

Cell Wall Porosity

AbstractThe thermal degradation of wood is affected by a number of process parameters, which may also cause variations in the resistance against decay fungi. This study compares changes in the chemical composition, water-related properties and decay resistance of Scots pine sapwood that was either thermally modified (TM) in dry state at elevated temperatures (≥ 185 °C) or treated in pressurized hot water at mild temperatures (≤ 170 °C). The thermal decomposition of easily degradable hemicelluloses reduced the mass loss caused by Rhodonia placenta, and it was suggested that the cumulative mass loss is a better indicator of an actual decay inhibition. Pressurized hot water extraction (HWE) did not improve the decay resistance to the same extent as TM, which was assigned to differences in the wood-water interactions. Cross-linking reactions during TM caused a swelling restraint and an effective reduction in moisture content. This decreased the water-swollen cell wall porosity, which presumably hindered the transport of degradation agents through the cell wall and/or reduced the accessibility of wood constituents for degradation agents. This effect was absent in hot water-extracted wood and strong decay occurred even when most hemicelluloses were already removed during HWE.

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Decay resistance, extractive content, and water sorption capacity of Siberian larch (Larix sibirica Lebed.) heartwood timber

Holzforschung ◽

10.1515/hf.2006.017 ◽

2006 ◽

Vol 60 (1) ◽

pp. 99-103 ◽

Cited By ~ 13

Author(s):

Martti Venäläinen ◽

Anni M. Harju ◽

Nasko Terziev ◽

Tapio Laakso ◽

Pekka Saranpää

Keyword(s):

Siberian Larch ◽

Brown Rot ◽

Decay Resistance ◽

Extractive Content ◽

Strong Negative Correlation ◽

Average Mass ◽

Brown Rot Fungi ◽

Hygroscopic Properties ◽

Decay Test

Abstract The aim of this study was to find chemical or physical properties of Siberian larch heartwood timber that correlate with the variation in decay resistance. Juvenile heartwood from 24-year-old grafts of 15 clones was exposed to three brown-rot fungi according to the standard in vitro decay test (European standard EN 113). The mass losses caused by the brown rot fungi Coniophora puteana, Poria placenta, and Gloeophyllum trabeum were 20%, 28% and 17% of the dry mass, respectively. The average mass loss over the three fungi had a strong negative correlation with the concentration of taxifolin (r=–0.673, P=0.006), as well as with the concentration of total phenolics determined by the Folin-Ciocalteu assay (r=–0.677, P=0.006). Thus, the concentration of flavonoids is a promising property for indirect measurement of the decay resistance of Siberian larch timber. The most abundant heartwood extractives, arabinogalactans, had a non-significant relationship with the decay resistance, but their concentration correlated positively with the capacity of the wood to adsorb water (r=0.736, P=0.002). The hygroscopic properties of the wood or the wood density were not associated with the decay resistance.

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Efficacy of Pinosylvins against White-Rot and Brown-Rot Fungi

Holzforschung ◽

10.1515/hf.1999.081 ◽

1999 ◽

Vol 53 (5) ◽

pp. 491-497 ◽

Cited By ~ 56

Author(s):

Catherine C. Celimene ◽

Jessie A. Micales ◽

Leslie Ferge ◽

Raymond A. Young

Keyword(s):

Picea Glauca ◽

Pinus Banksiana ◽

White Rot Fungi ◽

Brown Rot ◽

Monomethyl Ether ◽

Decay Resistance ◽

White Rot ◽

Red Maple ◽

Brown Rot Fungi ◽

Agar Media

Summary Three stilbenes, pinosylvin (PS), pinosylvin monomethyl ether (PSM) and pinosylvin dimethyl ether (PSD), were extracted from white spruce (Picea glauca), jack pine (Pinus banksiana), and red pine (Pinus resinosa) pine cones, and their structures were confirmed by spectroscopic and chromatographic (HPLC, GC/MS, NMR and FTIR) analysis. PS, PSM, PSD or a 1:1:1 mixture of these stilbenes at concentrations of 0.1 % and 1.0 % were examined for their fungal inhibitory activity by two bioassay methods. Growth of white-rot fungi (Trametes versicolor and Phanerochaete chrysosporium), and brown-rot fungi (Neolentinus lepideus, Gloeophyllum trabeum and Postia placenta) on agar media in the presence of each of the stilbenes or a 1:1:1 mixture inhibited growth of white-rot fungi, but slightly stimulated growth of brown-rot fungi. Soil-block assays, conditions more representative of those found in nature, did not correlate with those from the screening on agar media. PS, PSM, PSD or a 1:1:1 mixture of the three compounds at concentrations of 0.1 % and 1.0 % did not impart any significant decay resistance to white-rot fungi inoculated on a hardwood (Red maple). However under the same conditions, decay resistance was observed against brown-rot fungi on a softwood (Southern yellow pine). It appears that stilbenes at least partially contribute to wood decay resistance against brown-rot fungi.

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