Your search resulted in 27 documents. Displaying 25 entries per page.
Potentialities of protein borates as low-toxic, long-term wood preservatives - Preliminary trials
1999 - IRG/WP 99-30212
Boron compounds are efficient wood preservatives, as well as safe for the mammals and environmentally acceptable. Their natural solubility allows them to treat almost any wood species, but is also the cause of their high depletion from treated timber in outside exposure. In order to reduce this leachability, potentialities of proteinic polymer networks retaining boron within the wood have been inv...
M-F Thévenon, A Pizzi, J P Haluk
The influence of crystalline and amorphous cellulose on extracellular hydrogen peroxide production by brown-rot fungi
1991 - IRG/WP 1482
The production of hydrogen peroxide (H2O2) has been suggested to play a key role in the degradation of wood by wood-rotting fungi. The production of extracellular hydrogen peroxide was studied by a quantitative method which detects the oxidation of the 2,2-azinobis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) by H2O2 and horseradish peroxidase (HRP) in liquid culture medium. The carbon sources u...
A-C Ritschkoff, L Viikari
Non-enzymatic Gloeophyllum trabeum decay mechanisms: Further study
2001 - IRG/WP 01-10395
Information will be presented on the mechanisms involved in, and potential application of, non-enzymatic wood decay by brown rot decay fungi. Specifically, the hypothesized role of low molecular weight phenolate derivatives will be discussed in relation to non-enzymatic degradation of wood. The mechanism of binding of iron by cellulose, and binding and reduction of iron by fungal derivatives and m...
B Goodell, J Jellison
Wood degradation mechanisms by the brown rot fungus Gloeophyllum trabeum
1997 - IRG/WP 97-10229
A mechanism for the degradation of wood by the brown rot fungus Gloeophyllum trabeum is outlined. The mechanism includes the function of redox-cycling, low molecular weight phenolic derivatives which sequester and reduce iron in acidic environments. The role of oxalate for the sequestration of iron (hydr)oxides and the pH dependent transfer of iron to the G. trabeum phenolic chelators, as well as ...
B Goodell, J Jellison
Interaction mechanisms of F/Cr/As/B type preservative and wood
1981 - IRG/WP 3183
The paper reports results of investigations on the fixation of the components of a F/Cr/As/B preservative in wood and its lignin and cellulosic components....
N Ermush, I Andersone
Vapour boron treatment of wood based panels: Mechanism for effect upon impact resistance
1994 - IRG/WP 94-40036
Samples of medium density fibreboard, chipboard and oriented strandboard (OSB) were treated to two retentions of boric acid by a vapour phase treatment. The results of a range of mechanical tests were reported by Hashim et al. (1992, 1993) in which a small reduction in impact resistance was observed. Several investigations were carried out to study how and where this loss in impact resistance occu...
R Hashim, R J Murphy, D J Dickinson, J Dinwoodie
Albumin borate: A new non-toxic, wide-spectrum, long-term wood preservative
1998 - IRG/WP 98-30167
Boron, widely recognized for its broad range of activity towards both fungi and insects and for its low mammalian toxicity, can not provide long term protection to treated timber due to its high leachability. Boron, in the form of boric acid, can be partially fixed to timber by the formation of an association with egg albumin, which is insolubilized by heat-induced coagulation. Chemical investiga...
M-F Thévenon, A Pizzi, J-P Haluk
Microbial breakdown mechanisms. Mini-Symposium at the 18th IRG meeting, Honey Harbour, Ontario, Canada
1987 - IRG/WP 1327
An understanding of how micro-organisms cause chemical alternation to wood is essential for effective wood preservation. Investigation of the Microbial Breakdown of wood is a very dynamic research field and is increasing in importance as several biocides are being examined as alternativesw to classic wood preservatives. These biocides often do not possess broad spectrum activity. It is esential th...
L E Leightley
Preliminary studies of the decay mechanism of some brown-rot fungi
1989 - IRG/WP 1402
The importance of the enzymatic degradation of hemicellulose and cellulose by brown-rot fungi is still under discussion. Endo-ß-1,4-xylanase and endoglucanase activities of Coniophora puteana and Poria placenta cultures were measured by the increase in reducing groups. Enzymes were produced in liquid and solid sawdust based culture media. Enzyme activities were measured in two, four and eight wee...
A-C Ritschkoff, H Viitanen
Biochemical aspects of white-rot and brown-rot decay
1987 - IRG/WP 1319
This paper presents an overview of the decomposition of wood by white- and brown-rot fungi - the most important and potent of known wood-decay fungi. These organisms are unique among cellulose destroyers because of their strong capability to enzymatically degrade lignified material. Special emphasis is given to the following aspects of wood decomposition by white- and brown-rot fungi: (1) effects...
T L Highley
Fenton's reagent as a modification tool in brown-rot decay
1996 - IRG/WP 96-10155
A biomimetic approach was used to clarify the role and importance of the Fenton-type reaction in the carbohydrate degradation by brown-rot fungi. Spruce sawdust and microcrystalline cellulose were modified in the H2O2/Fe(II) treatment. The degree of hydrolysis of the pretreated spruce sawdust was clearly increased with the complete cellulase (Econase), purified endoglucanase from Trichoderma reese...
M Rättö, A-C Ritschkoff, J Buchert, L Viikari
Production of exraxellular hydrogen peroxide and oxalic acid by brown-rot fungus Poria placenta
1995 - IRG/WP 95-10112
Hydrogen peroxide and oxalic acid have been suggested to be essential in the degradation of wood carbohydrates by brown-rot fungi. Hydrogen peroxide has been suggested to be one of the diffusible low molecular weight agents produced by brown-rot fungi for the degradation of wood carbohydrates by generating highly active radicals. The production of hydrogen peroxide and oxalic acid by Poria placent...
A-C Ritschkoff, M Rättö, J Buchert, L Viikari
Mechanisms of Protection by NHA Against Fungal Decay
2002 - IRG/WP 02-10429
Treating wood with the water-borne sodium salt of N'-N-naphthaloylhydroxylamine (Na-NHA) protects wood against decay and termite damage. Initial testing indicated little or no inhibition of sapstain fungi, molds, or soft-rot fungi by Na-NHA, suggesting that the mechanism by which this compound protected wood was complex and not that of a broad-spectrum biocide. Previously, we (Green et...
F Green III, W Henry, T Schultz
Assessing the importance of degradation mechanisms on the loss of effectiveness of wood preservatives
2000 - IRG/WP 00-20193
Accelerated ageing systems developed for application to samples in the laboratory prior to biological tests, should reflect those natural deterioration processes that are likely to occur in the hazard classes defined in EN 335-1. Losses through evaporation or the effects of leaching have been recognised, however their importance, relative to other mechanisms has not been quantified. Degradation me...
E D Suttie, R J Orsler, T Dearling
Hydrolysis of bordered pits during colonization of conifers by brown-rot fungi
1995 - IRG/WP 95-10103
Brown-rot decay results in rapid reduction in degree of polymerization (DP) of holocellulose with concomitant strength loss (MOR) without removing lignin. Development of new methods of wood protection will require focusing on early events in the sequence of depolymerization. Bordered pit membranes (sapwood) represent a readily available source of non-lignified carbohydrate, ie. pectin and cellulos...
F Green III, J L Tschernitz, T A Kuster, T L Highley
Copper based wood preservative - A new approach using fixation with resin acids of rosin
2000 - IRG/WP 00-30249
Copper soaps with carboxylic acid groups of resin acids of rosin were shown to be potential long-term wood preservatives. The principle involved is the attachment of copper to the network formed by the inorganic part of the preservative (rosin) through the -COOH groups. The mechanisms of fixation have been studied, and it has been shown that this association could be obtained : (1) by forming the ...
C Roussel, J P Haluk, A Pizzi, M-F Thévenon
Examination of preservative-treated Pinus sylvestris using electron paramagnetic resonance
1992 - IRG/WP 92-3710
EPR is currently being used to help elucidate the nature and extent of the chemical reactions occurring between wood and copper based timber preservatives. In the work reported here treated Scots pine samples were examined at room temperature and in the frozen state. Plots of the electronic parameters A|| vs. g|| were found to be a useful index of the electronic properties of the various formulati...
A S Hughes, R J Murphy, J F Gibson, A J Cornfield
The identification of the carbohydrate degrading enzymes from the crude extract of brown-rot fungus Gloeophyllum trabeum
1991 - IRG/WP 1483
The brown-rot fungus, Gloeophyllum trabeum, produces a pattern of carbohydrate degrading enzymes during the wood decay. In liquid sawdust media the activities of endo-b-1,4-gluganase and endo-b-1,4-xylanase were at the maximum after 5-6 weeks cultivation. The production of enzymes started immediately after inoculation suggesting that the degradation of hemicellulose and easily degradable parts of ...
A-C Ritschkoff, J Buchert, L Viikari
Chemical reactions involved in furfurylation of solid wood - An investigation by ATR-IR spectroscopy
2006 - IRG/WP 06-40347
Wood modification with furfuryl alcohol (FA) has gained renewed interest during the last five to ten years because of advances in process technology and because of increased focus on the environmental hazards of traditional wood impregnation. The reaction mechanisms involved in the furfurylation process are not yet understood in detail. In the work presented here, the chemical reactions and their ...
T Mark Venås, L Garbrecht Thygesen, S Barsberg
Protection mechanisms of modified wood against decay by white and brown rot fungi
2010 - IRG/WP 10-10713
The resistance of beech and pine wood blocks treated with 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU) against T. versicolor and C. puteana increased with increasing WPG. Full protection (mass loss below 3%) was reached at WPGs of approximately 15% (beech) and 10% (pine). Metabolic activity of the fungi in the wood blocks was assessed as heat or energy production determined by isothermal mic...
C Mai, P Verma, Yanjun Xie, J Dyckmans, H Militz
Fungal Attack on Lignin and Cellulose: Elucidation of Brown- and White-Rot Mechanisms Comparing Biomimetic and In-Vivo Degradation Patterns
2010 - IRG/WP 10-10714
This paper examines research and hypotheses that have been developed over several years on wood degradation mechanisms. This information is combined with new data and analyses to explain why wood decay patterns caused by brown-rot fungi and specific types of white-rot fungi are different. New data, including work with both biomimetic studies on low molecular weight compounds, degradative enzymes, ...
V Arantes, B Goodell, A M F Milagres, Yuhui Qian, T Filley, J Jellison, S Kelley
A survey of factors affecting decay resistance of wood modified with acetic anhydride
2012 - IRG/WP 12-40594
From the range of information published, acetylation appears well suited to provide adequate protection against biological attack for materials derived from typically non-durable wood species. Acetylated wood is now commercially available both in Europe and in the USA. But still there are a lot of unanswered questions related to fungal decay mechanisms in acetylated wood. The paper summarize exist...
G Alfredsen, P O Flæte, H Militz
The Chelator Mediated Fenton System in the Brown Rot Fungi: Details of the Mechanism, and Reasons Why it has Been Ineffective as a Biomimetic Treatment in some Biomass Applications – a Review
2014 - IRG/WP 14-10828
The chelator-mediated Fenton (CMF) reaction requires the action of two types of chelating compounds. The first chelator, oxalate, solubilizes and then sequesters iron, and the second chelator reduces iron. Iron reduction must be controlled near the fungal hyphae to prevent damaging Fenton chemistry from occurring in that location. Similarly, iron reduction must be promoted within the wood/plant ce...
B S Goodell, M Nakamura, J Jellison
Enhancing Our Understanding of Brown Rot Mechanisms through Catalytic Pretreatment and Cellulase Cocktail
2018 - IRG/WP 18-10909
A catalytic mechanism, described as the “chelator-mediated Fenton” (CMF) mechanism, is proposed to mimic the non-enzymatic action of brown rot fungi. A CMF treatment was used together with an enzymatic cocktail to study how wood was deconstructed and solubilized. This was done in-part to determine if the treatment mimicked the action of brown rot fungi, but also to explore improved treatment p...
S Tabor, L Orjuela, D Contreras, G Alfredsen, J Jellison, S Renneckar, B Goodell
Non-stochiometric oxidation and ROS generation promoted by guaiacol lignin structures and lignocelluose surfaces may be a component of brown rot fungal degradation mechanisms
2019 - IRG/WP 19-10937
Model guaiacol compounds representing lignin monomers, as well as DHP-lignin and wood flour of controlled particle size were used to assess iron reduction at the pH of the natural wood cell wall. All compounds functioned as electron donors for ferric iron, with the lignin monomers demonstrating capacity for non-stochiometric reduction of iron with multiple moles of ferric ion reduced per mole of l...
Y Tamarua, M Yoshidaa, L D Eltisb, B Goodell