Treatment of wood with silica sols against attack by wood-decaying fungi and blue stain

Holzforschung ◽  
2013 ◽  
Vol 67 (6) ◽  
pp. 697-705 ◽  
Author(s):  
Malte Pries ◽  
Carsten Mai

Abstract Pine sapwood was treated with various types of silica sols. Whereas alkaline sols were not able to penetrate deeper into wood, neutral and acidic sols showed good penetration. The weight percent gain of treated specimens amounted to 20–25%; bulking was negligible or even slightly negative. All silica sols in the treated specimens were stable against water leaching. A water submersion test revealed hydrophobation of the wood only after treatment with a cationic silica sol; all other silica sols increased the rate of water uptake. The addition of 2% cationic sol to a malt-agar growth medium caused growth inhibition of 40–50% of the wood decay fungi Coniophora puteana and Trametes versicolor, whereas the other silica sols did not inhibit growth. Pine sapwood and beech wood blocks treated with the cationic sol showed a strong reduction in mass loss compared to the control samples after incubation with C. puteana (pine) and T. versicolor (beech) according to EN 113 and CEN/TS 15083-1; all other silica sols did not inhibit fungal decay. The cationic silica sol reduced blue staining by Aureobasidium pullulans compared to the untreated control but did not fully prevent it; all other silica sols did not inhibit blue staining.

Holzforschung ◽  
2013 ◽  
Vol 67 (4) ◽  
pp. 447-454 ◽  
Author(s):  
Malte Pries ◽  
Roland Wagner ◽  
Karl-Heinz Kaesler ◽  
Holger Militz ◽  
Carsten Mai

Abstract Blocks of pine sapwood and beech wood were treated with water-based emulsions containing short-chain silicones with different α-ω-bonded functional groups, such as diamino, carboxyl and carbonyl, betain, and epoxy groups. The weight percent gain upon treatment of the pine wood specimens was relatively high (10%–20%), but their cross-sectional bulking was low (1%–2.5%). Thus, the anti-shrink efficiency (ASE) due to the treatment was also low. The first water-submersion tests revealed some hydrophobation of the treated wood. A second submersion test, however, revealed successful hydrophobation only for betain-functionalised material. The carboxylated silicone even increased the speed of water uptake as compared to the controls. The samples treated with silicones bearing epoxy, diamino, and carboxy functionalities showed a distinct reduction in mass loss compared to the control samples after 16 weeks of incubation with the fungi Coniophora puteana and Trametes versicolor according to EN 113 and CEN/TS 15083-1, whereas the betain-functionalised silicone did not enhance fungal resistance. All silicones tested lowered the mass loss in a soft rot test according to ENv 807. The mode of action of the silicones is discussed.


Holzforschung ◽  
2020 ◽  
Vol 74 (12) ◽  
pp. 1135-1146
Author(s):  
Wanju Li ◽  
Minghui Liu ◽  
Hankun Wang ◽  
Yan Yu

AbstractIn order to improve dimensional stability and durability of wood, furfurylation of poplar and Chinese fir wood using newly developed furfuryl alcohol (FA) formulation combined with a common vacuum and pressure impregnation process was studied. An orthogonal experiment was designed to optimize the furfurylation process for the two wood species. The weight percent gain (WPG), equilibrium moisture content (EMC), anti-swelling efficiency (ASE), modulus of rupture (MOR), modulus of elasticity (MOE), as well as resistance to mold, decay fungi, and termites were evaluated. The results showed that nearly all the properties of the furfurylated wood could be improved to various extents. The average ASE of the furfurylated Chinese fir and poplar could reach as high as 80, 71, 92% and 79, 90, 75% in tangential and radial directions, and by volume, respectively, higher than most previously reported wood modification processes. Furthermore, the modified wood had excellent biological durability, with nearly 100% mold resistance, strong decay and termite resistance. Finally, processing parameters with 50% FA, 105–115 °C curing temperature, and 5–8 h curing time were therefore recommended for pilot-scale production of furfurylated poplar and Chinese fir wood based on range analysis.


Author(s):  
Cédric Cabral Almada ◽  
Mathilde Montibus ◽  
Frédérique Ham-Pichavant ◽  
Sandra Tapin-Lingua ◽  
Gilles Labat ◽  
...  

1985 ◽  
Vol 63 (2) ◽  
pp. 337-339 ◽  
Author(s):  
Elmer L. Schmidt

Influences of eight saturated aliphatic acids (C5–C10, C12, and C16) on basidiospores of four isolates of wood-decay fungi (Poria tenuis and Trametes hispida, white rot fungi, and two isolates of the brown rot fungus Gloeophyllum trabeum) were observed in vitro. Spore responses after 24 h on malt extract agar containing 10, 102 or 103 ppm of each acid included normal germination, delay of germ tube emergence, vacuolation and degeneration of spore cytoplasm, and prevention of germ tube development without spore destruction. Acids of chain length C5–C10 prevented spore germination and killed spores of all fungi at concentrations of 20–50 ppm in media, whereas other acids tested were less active. Spore germination assay of decay fungi may prove useful as a screening tool to compare potency of wood preservatives.


2009 ◽  
pp. 151-181 ◽  
Author(s):  
Sarah Watkinson ◽  
Dan Bebber ◽  
Peter Darrah ◽  
Mark Fricker ◽  
Monika Tlalka ◽  
...  

2012 ◽  
Vol 518-523 ◽  
pp. 29-33 ◽  
Author(s):  
Peng Fei Xiao ◽  
Toshio Mori ◽  
Ryuichiro Kondo

Although heptachlor epoxide is one of the most persistent organic pollutants (POPs) that cause serious environmental problems, there is very limited information of the biodegradation of heptachlor epoxide by microorganisms, and no systematic study on the metabolic products and pathway of endrin by microorganisms has been conducted. Wood-decay fungi can degrade a wide spectrum of recalcitrant organopollutants, including polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated biphenyls (PCBs). In this study, 18 wood-decay fungi strains of genus Phlebia were investigated for their ability to degrade heptachlor epoxide, and Phlebia acanthocystis, Phlebia brevispora, Phlebia lindtneri and Phlebia aurea removed about 16, 16, 22 and 25% of heptachlor epoxide, respectively, after 14 days of incubation. Heptachlor diol and 1-hydroxy-2,3-epoxychlordene were detected in these fungal cultures as metabolites by gas chromatography and mass spectrometry (GC/MS), suggesting that the hydrolysis reaction in the epoxide ring and substitution of chlorine atom with hydroxyl group in C1 position occur in bioconversion of heptachlor epoxide by selected wood-decay fungi, respectively. This is the first report describing the metabolites of heptachlor epoxide by microorganisms.


2017 ◽  
Vol 31 (4) ◽  
pp. 566-570 ◽  
Author(s):  
Georgea S. Nogueira-Melo ◽  
Paulo J. P. Santos ◽  
Tatiana B. Gibertoni

Hoehnea ◽  
2016 ◽  
Vol 43 (4) ◽  
pp. 575-581 ◽  
Author(s):  
Thiara Siqueira Bento ◽  
Luce Maria Brandão Torres ◽  
Mauricio Batista Fialho ◽  
Vera Lúcia Ramos Bononi

ABSTRACT White-rot basidiomycetes are able to deteriorate wood products and be pathogenic to living trees, requiring, thus requiring control. The tropical flora is an important source of eco-friendly antifungal compounds; however, the knowledge on how leaf extracts affect the fungal physiology is limited. Therefore, in the present work we investigated the influence of ethanolic leaf extracts of Casearia sylvestris and C. decandra at 0.1 mg mL-1 on the production of ligninolytic enzymes by Trametes villosa, Ganoderma australe and Pycnoporus sanguineus. Overall, the extracts inhibited the mycelial growth and the production of biomass. Additionally, C. sylvestris extract reduced the production of manganese peroxidase and laccase; however, the exposure to C. decandra extract resulted in variable responses. Therefore, enzymes related to lignin degradation are potential targets to control wood decay fungi by plant bioactive compounds, as their ability to colonize the substrate may be impaired.


2021 ◽  
Vol 12 ◽  
Author(s):  
Shuo Cao ◽  
Yang Yang ◽  
Guiqi Bi ◽  
David Nelson ◽  
Sheng Hu ◽  
...  

Many fungi form persistent and dormant sclerotia with compact hardened mycelia during unfavorable circumstances. While most of these sclerotia are small in size, Wolfiporia cocos, a wood-decay fungus, grows into giant sclerotia, which are mainly composed of polysaccharides of linear (1→3)-β-D-glucans. To explore the underlying mechanism of converting sophisticated wood polysaccharides for biosynthesis of highly homogenized glucans in W. cocos, we sequenced and assembled the genome of a cultivated W. cocos strain (WCLT) in China. The 62-Mb haploid genome contains 44.2% repeat sequences, of which, 48.0% are transposable elements (TEs). Contrary to the genome of W. cocos from North America, WCLT has independently undergone a partial genome duplication (PGD) event. The large-scale TE insertion and PGD occurrence overlapped with an archeological Pleistocene stage of low oxygen and high temperature, and these stresses might have induced the differences in sclerotium due to geographical distribution. The wood decomposition enzymes, as well as sclerotium-regulator kinases, aquaporins, and highly expanded gene families such as NAD-related families, together with actively expressed 1,3-β-glucan synthase for sclerotium polysaccharides, all have contributed to the sclerotium formation and expansion. This study shall inspire further exploration on how fungi convert wood into simple glucans in the sclerotium of W. cocos.


Sign in / Sign up

Export Citation Format

Share Document