Your search resulted in 49 documents. Displaying 25 entries per page.
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
Effect of wood polymers degradation during heat treatment on extracellular enzymatic activities involved in beech degradation by Trametes versicolor
2008 - IRG/WP 08-40392
Effect of heat treatment on extracellular enzymes involved in wood degradation by Trametes versicolor was investigated. Heat-treated and untreated beech blocks were exposed to T. versicolor on malt agar medium and extracellular enzymatic activities investigated. A strong ABTS oxidizing activity has been detected during the first stage of colonization in both cases, while cellulase activities are m...
S Lekounougou, G Nguila Inari, M Pétrissans, S Dumarçay, J P Jacquot, E Gelhaye, P Gérardin
Aislamiento, identificación y evaluación enzimática de hongos de pudrición de madera de la Región de los Lagos
2008 - IRG/WP 08-10680
So far, systematic investigations have not been developed to determine the fungal diversity associated with wood in Chile. In addition, little is known about the mycoflora capabilities or their enzymatic processes in biotechnology although different research has hinted at the great potential of these microorganisms in various industrial processes. The aim of this work is to isolate, identify and e...
R Ortiz, J Navarrete, C Oviedo, R Blanchette
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
Chemical mediated depolymerization of cotton cellulose for the understanding of non-enzymatic fungal decay
2010 - IRG/WP 10-10731
Small, low molecular weight non-enzymatic compounds have been linked to the early stages of brown rot decay as the enzymes involved with holocellulose degradation are found to be too large to penetrate the S3 layer of intact wood cells. The most pronounced of these which were analyzed in this study are hydrogen peroxide, iron, and oxalic. The compounds related to the Fenton reaction: the combinati...
A C Steenkjær Hastrup, B Jensen, F Green III
Wood decay enzymatic ability of Fusarium circinatum
2012 - IRG/WP 12-10777
There exists pathogens that attack standing trees of forests, and do not usually thrive once the tree is felled. However, occasionally they can be present in a latent state in the wood and can spread and affect new areas with economic, ecological and social consequences. Fusarium circinatum is a fungus that causes “pitch canker” in pine species, and is considered a quarantine organism within t...
M T Troya, F Llinares, Y Serrano, M Conde
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
Scanning Transmission X-ray Microscopy as a tool for examining chemical changes in wood cell walls due to enzymatic activity
2014 - IRG/WP 14-20556
As development of techniques for examining enzymatic activity on solid, complex biological materials, is considered to be an important factor in further development of enzyme applications and for understanding the decay of plant materials, this study explores applicability of Scanning Transmission X-ray Microscope (STXM) for determining chemical changes in enzymatically treated samples at the cell...
D Jeremic, R Goacher, R Yan, C Karunakaran, E R Master
Possible targets of wood modification in brown rot degradation
2014 - IRG/WP 14-40676
Wood modification protects wood from fungal degradation in a non-toxic manner. However, the mechanisms behind the decay resistance in modified wood are currently unknown. The aim of this study was to discuss the i) colonisation, ii) nutrient recognition, iii) transcription, iv) depolymerisation and v) hydrolysis steps in the brown rot degradation progress and explore whether they are inhibited by ...
R Ringman, A Pilgård, G Alfredsen, B Goodell, K Richter
A novel enzymatic treatment as a new approach for wood protection
2015 - IRG/WP 15-40701
Wood durability is a worldwide concern and most treatments tend to fail with regard to their efficacy along the time. Weather conditions lead to a loss of the treatment substances into the surrounding environment and, in consequence, generate also a public health concern.
Recently, the employment of oxidative enzymes, such as laccases, has been proposed as a tool for lignocellulosics modificatio...
C Fernández-Costas, S Palanti, M Ángeles Sanromán, D Moldes
Foundation piles: analysis of beech wood decay in service life conditions
2016 - IRG/WP 16-10858
Wood piles foundation system was largely used over decades. Thus, numerous buildings over the world are based on this constructive system. In the context of reduction of CO2 emissions in the building field of constructions, substitution of concrete by wood as material for foundation piles seems to be a promising alternative. However, fluctuation of the water table level in soil may promote fungal ...
Q Kleindienst, A Besserer, M-L Antoine, C Perrin, J-F Bocquet, L Bléron
Wood properties modification by an enzymatic assisted treatment with phenolic extractives
2016 - IRG/WP 16-30696
Extractives of sawdust and bark from P. pinaster and, condensed tannins (CTs) from P. radiata bark were used to treat beech and pine veneers in combination with an oxidative enzyme, in order to stably graft such extractives onto the veneers. First, the antifungal activity of P. pinaster phenolic extractives against wood decay fungi was studied. These extractives were also used to hydrophobize pi...
D Filgueira, C Fernández-Costas, D E García, D Moldes
Investigation of enzymatic effect on pit membranes by light and scanning electron microscopy
2016 - IRG/WP 16-40721
Spruce wood, one of the refractory wood species has pit membranes, which has an influence on the permeability of wood providing liquid flow between the wood cells. However, these membranes tend to close under the fiber saturated point (FSD), which makes impregnation more difficult. In this study spruce sapwood samples were treated with two different commercial enzymes to improve the permeability o...
S Durmaz, Ü C Yildiz, M Öztürk, B Serdar
New perspectives for wood protection: enzyme-based treatments
2016 - IRG/WP 16-40742
Wood protection research is continuously looking for more benign and effective treatments. One of the main concerns deals with the toxicity of the active compounds employed in the formulations of the preservatives, since they could become a health and environmental issue. Secondly, long-lasting treatments are preferred in order to increase the service life of the treated wood. Weathering condition...
C Fernández-Costas, S Palanti, M Á Sanromán, D Moldes
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
Using X-ray scattering to elucidate the mechanisms behind the moisture and fungal decay resistance of epoxybutene modified wood
2019 - IRG/WP 19-40854
Chemical modification of the hydroxyl groups of wood can improve the properties of wood by providing moisture and biological resistance, as well as dimensional stability. Southern pine solid wood was chemically modified to various weight percentage gains (WPG) with epoxybutene (EpB, 8%-38% WPG). After modification, specimens were extracted with a toluene: ethanol (2:1) solution for 2 hours or wate...
R E Ibach, N Plaza
Different levels of acetylation lead to groupwise upregulation of non-enzymatic wood degradation genes of Rhodonia placenta during initial brown-rot decay
2020 - IRG/WP 20-10958
Rhodonia placenta, often used as a model fungus to represent brown rot fungi, uses a two-stepped degradation mechanism to degrade wood. Regarding the overcoming of wood protection systems the initial degradation phase seems to be the crucial point. A new laboratory test enables the separation of the non-enzymatic oxidative and the enzymatic degradation phases, which has previously been proven chal...
M Kölle, R Ringman, A Pilgård
Effect of enzymatic inhibitors on the population of Reticulitermes grassei and their associated microbiota
2023 - IRG/WP 23-11008
Termites are pests that invade urban, agricultural and forest environments worldwide. They are economically important owing to the damage they cause to wood, wood products, building materials, agricultural products and forests. There are many methods for its control, but many of them cause negative environmental effects due to their toxicity. In termites, dietary change or antibiotic treatment may...
S M Santos, M T Troya, F Llinares, P Colina, E García, M Álvarez, L Robertson
Isolation of the microbiota from wood decay insects and some of their enzymatic activities
2023 - IRG/WP 23-11014
Wood decay organisms have the ability to degrade wood components (cellulose, hemicellulose and lignin) by enzymatic capacities, but these enzymes can belong to the proper organism, or to the associated microbiota. The identification of the microorganisms, as well as their role in the digestion of many substrates not always is very well known.
The wood decay insects produce big damages in wood str...
M T Troya, F Llinares, J Arranz, S Izpura-Luis, S M Santos, L Robertson
How the biochemical activities of polyphenols may be effective for the protection of wood deterioration by termites?
2023 - IRG/WP 23-30789
In spite of the remarkable mechanical characteristics of wood for building construction and furniture industry, this material is prone to biodeterioration by xylophagous organisms. This compromises its durability and performances during storage and services, and results in considerable economical losses estimated by the billions. Protection against fungi, termites and other wood biodegrading organ...
J-P Joseleau, D Messaoudi, K Ruel