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Publikasjoner (10 av 13) Visa alla publikasjoner
Ringman, R., Beck, G. & Pilgård, A. (2019). The importance of moisture for Brown Rot degradation of Modified Wood: A critical discussion. Forests, 10(6), Article ID 522.
Åpne denne publikasjonen i ny fane eller vindu >>The importance of moisture for Brown Rot degradation of Modified Wood: A critical discussion
2019 (engelsk)Inngår i: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 10, nr 6, artikkel-id 522Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The effect of wood modification on wood-water interactions in modified wood is poorly understood, even though water is a critical factor in fungal wood degradation. A previous review suggested that decay resistance in modified wood is caused by a reduced wood moisture content (MC) that inhibits the diffusion of oxidative fungal metabolites. It has been reported that a MC below 23%-25% will protect wood from decay, which correlates with the weight percent gain (WPG) level seen to inhibit decay in modified wood for several different kinds of wood modifications. In this review, the focus is on the role of water in brown rot decay of chemically and thermally modified wood. The study synthesizes recent advances in the inhibition of decay and the effects of wood modification on the MC and moisture relationships in modified wood. We discuss three potential mechanisms for diffusion inhibition in modified wood: (i) nanopore blocking; (ii) capillary condensation in nanopores; and (iii) plasticization of hemicelluloses. The nanopore blocking theory works well with cell wall bulking and crosslinking modifications, but it seems less applicable to thermal modification, which may increase nanoporosity. Preventing the formation of capillary water in nanopores also explains cell wall bulking modification well. However, the possibility of increased nanoporosity in thermally modified wood and increased wood-water surface tension for 1.3-dimethylol-4.5-dihydroxyethyleneurea (DMDHEU) modification complicate the interpretation of this theory for these modifications. Inhibition of hemicellulose plasticization fits well with diffusion prevention in acetylated, DMDHEU and thermally modified wood, but plasticity in furfurylated wood may be increased. We also point out that the different mechanisms are not mutually exclusive, and it may be the case that they all play some role to varying degrees for each modification. Furthermore, we highlight recent work which shows that brown rot fungi will eventually degrade modified wood materials, even at high treatment levels. The herein reviewed literature suggests that the modification itself may initially be degraded, followed by an increase in wood cell wall MC to a level where chemical transport is possible.

sted, utgiver, år, opplag, sider
MDPI AG, 2019
Emneord
Acetylation, Brown rot fungi, Capillary condensation, Diffusion, Furfurylation, Hemicellulose plasticization, Moisture content, Porosity, Thermal modification, Wood water relationships, Biodegradation, Cellulose, Chemical modification, Condensation, Crosslinking, Decay (organic), Fungi, Moisture, Moisture determination, Nanopores, Wood
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-39645 (URN)10.3390/f10060522 (DOI)2-s2.0-85068898205 (Scopus ID)
Merknad

Funding details: Vetenskapsrådet, VR; Funding text 1: R.R. and A.P. gratefully acknowledge financial support from The Swedish Research Council Formas 942-2015-530

Tilgjengelig fra: 2019-08-07 Laget: 2019-08-07 Sist oppdatert: 2019-08-07bibliografisk kontrollert
Ringman, R., Pilgård, A., Brischke, C., Windeisen, E. & Richter, K. (2017). Incipient brown rot decay in modified wood: patterns of mass loss, structural integrity, moisture and acetyl content in high resolution. International Wood Products Journal, 8(3), 172-182
Åpne denne publikasjonen i ny fane eller vindu >>Incipient brown rot decay in modified wood: patterns of mass loss, structural integrity, moisture and acetyl content in high resolution
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2017 (engelsk)Inngår i: International Wood Products Journal, ISSN 2042-6445, E-ISSN 2042-6453, Vol. 8, nr 3, s. 172-182Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The study of degradation and growth patterns of fungi in modified wood may increase the understanding of their mode of action and may lead to more accurate service-life predictions. The aim of this paper was to study the degradation and growth patterns of brown rot fungi in modified wood and to measure moisture content (MC), structural integrity and the acetyl content by frequent monitoring over 300 days. Mass loss (ML) in the modified wood materials increased slowly up to 3% for 50–100 days after which it flattened out and remained constant during the remainder of the test. Structural integrity and acetyl content were maintained in the modified wood materials and MC was lower compared to untreated wood throughout the decay test. ML results of untreated wood indicate that fungi in solid wood go through distinct phases; the degradation patterns in the modified wood materials were more difficult to interpret.

Emneord
Acetylated wood, basidiomycetes, furfurylated wood, growth phases, mode of action, Postia placenta, wood degradation, wood modification, Biodegradation, Fungi, Growth rate, Moisture, Structural integrity, Growth phasis, Postia placentas, Wood
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-30268 (URN)10.1080/20426445.2017.1344382 (DOI)2-s2.0-85022062402 (Scopus ID)
Forskningsfinansiär
Swedish Research Council Formas, 2011-1481
Tilgjengelig fra: 2017-08-11 Laget: 2017-08-11 Sist oppdatert: 2019-02-05bibliografisk kontrollert
Ringman, R., Pilgård, A., Kölle, M., Brischke, C. & Richter, K. (2016). Effects of thermal modification on Postia placenta wood degradation dynamics: measurements of mass loss, structural integrity and gene expression. Wood Science and Technology, 50(2), 385-397
Åpne denne publikasjonen i ny fane eller vindu >>Effects of thermal modification on Postia placenta wood degradation dynamics: measurements of mass loss, structural integrity and gene expression
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2016 (engelsk)Inngår i: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 50, nr 2, s. 385-397Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The mechanism by which modified wood resists decay has long been discussed, but is still not fully understood. A better understanding of decay resistance mechanisms could improve wood protection processes and product properties. In this study, the dynamics of brown rot decay in thermally modified wood was examined through measurements of mass loss, strength loss and gene expression. Close monitoring of mass loss over 120 days in thermally modified wood exposed to Postia placenta showed a delay in the onset of degradation compared to untreated wood, and once the degradation had started, the rate was lower. Thermally modified wood did not inhibit expression of wood degradation-related genes before mass loss and was similar to that in untreated wood once mass loss could be detected. Comparing gene expression as well as strength loss at the same stage of decay rather than at the same time after exposure showed smaller differences in decay patterns between thermally modified and untreated wood than previous results indicate. It is concluded that the key to understanding degradation resistance in thermally modified wood is to compare the decay patterns in thermally modified wood and untreated wood before mass loss occurs.

sted, utgiver, år, opplag, sider
Springer Berlin/Heidelberg, 2016
Emneord
Mass Loss, Thermal Modification, Alcohol Oxidase, Wood Cell Wall, Untreated Wood
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-390 (URN)10.1007/s00226-015-0791-z (DOI)
Tilgjengelig fra: 2016-06-22 Laget: 2016-06-22 Sist oppdatert: 2019-06-13bibliografisk kontrollert
Alfredsen, G., Ringman, R., Pilgård, A. & Fossdal, C. G. (2015). New insight regarding mode of action of brown rot decay of modified wood based on DNA and gene expression studies: A review (ed.). International Wood Products Journal, 6(1), 5-7
Åpne denne publikasjonen i ny fane eller vindu >>New insight regarding mode of action of brown rot decay of modified wood based on DNA and gene expression studies: A review
2015 (engelsk)Inngår i: International Wood Products Journal, ISSN 2042-6445, E-ISSN 2042-6453, Vol. 6, nr 1, s. 5-7Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Modified wood shows resistance against wood deteriorating fungi, but the mechanisms are still not fully understood. The aim of this paper was to summarise the molecular studies performed on modified wood with regard to brown rot decay fungi. The DNA data showed that fungi are present inside the laboratory wood test samples already after two weeks of inoculation. Generally the fungal DNA content reflects mass loss and wood moisture content. The oxidative gene expression seems to be higher in modified wood than in untreated wood and it tend to increase during incubation. Based on the gene expression data we suggest that the hypothesis of lack of substrate recognition by the fungus should be rejected. In the reviewed studies, total wood moisture content in the samples was generally not low enough to inhibit fungal colonisation. Hence, moisture distribution within the wood should be studied more closely.

Emneord
Acetylation, Dmdheu, Enzymatic degradation, Furfurylation, Moisture, Oxidative degradation, Thermal modification
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-6835 (URN)10.1179/2042645314Y.0000000085 (DOI)23632 (Lokal ID)23632 (Arkivnummer)23632 (OAI)
Tilgjengelig fra: 2016-09-08 Laget: 2016-09-08 Sist oppdatert: 2019-07-05bibliografisk kontrollert
Ringman, R., Pilgård, A. & Richter, K. (2014). Effect of wood modification on gene expression during incipient Postia placenta decay (ed.). International Biodeterioration & Biodegradation, 86(B), 86-91
Åpne denne publikasjonen i ny fane eller vindu >>Effect of wood modification on gene expression during incipient Postia placenta decay
2014 (engelsk)Inngår i: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 86, nr B, s. 86-91Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The mode of action of nontoxic wood modifications and the fungal response to modified wood are not fully elucidated. The aim of this study was to investigate the reaction of Postia placenta in terms of gene expression of selected genes upon the encounter of acetylated, DMDHEU-treated and thermally modified wood. Quantitative PCR (qPCR) showed that the investigated P.placentagenes involved in oxidative degradation were expressed at higher levels in modified wood than in untreated wood, while expression levels in modified wood for the investigated genes involved in enzymatic degradation were slightly lower than those in untreated wood. The results indicate that the response of P.placenta upon the encounter of modified wood is to up-regulate the expressionof the oxidative degradation machinery. In addition, our results support the theory that the decay resistance of the herein studied modified woods is due to inhibition of fungal molecules, needed for oxidative degradation of wood polymers, to penetrate the wood cell wall.

HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-6605 (URN)10.1016/j.ibiod.2013.09.002 (DOI)2-s2.0-84888063324 (Scopus ID)15250 (Lokal ID)15250 (Arkivnummer)15250 (OAI)
Tilgjengelig fra: 2016-09-08 Laget: 2016-09-08 Sist oppdatert: 2019-08-09bibliografisk kontrollert
Pilgård, A., Ringman, R., Kölle, M., Brischke, C. & Richter, K. (2014). Expression of Postia placenta wood degradation genes in thermally modified wood (ed.). In: Proceedings of 10th Meeting of the Northern European Network for Wood Science & Engineering (WSE 2014): . Paper presented at 10th Meeting of the Northern European Network for Wood Science & Engineering (WSE 2014). Edited by Peter Wilson. Edinburgh Napier University
Åpne denne publikasjonen i ny fane eller vindu >>Expression of Postia placenta wood degradation genes in thermally modified wood
Vise andre…
2014 (engelsk)Inngår i: Proceedings of 10th Meeting of the Northern European Network for Wood Science & Engineering (WSE 2014), Edinburgh Napier University , 2014, , s. 97-103Konferansepaper, Publicerat paper (Fagfellevurdert)
sted, utgiver, år, opplag, sider
Edinburgh Napier University, 2014. s. 97-103
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-12364 (URN)16577 (Lokal ID)16577 (Arkivnummer)16577 (OAI)
Konferanse
10th Meeting of the Northern European Network for Wood Science & Engineering (WSE 2014). Edited by Peter Wilson
Tilgjengelig fra: 2016-09-13 Laget: 2016-09-13 Sist oppdatert: 2018-08-15bibliografisk kontrollert
Ehmcke, G., Ringman, R., Pilgård, A. & Richter, K. (2014). Improvement of a cytochemical method for localization of hydrogen peroxide and adaptation to furfurylated wood (ed.). In: Proceedings of 10th Meeting of the Northern European Network for Wood Science & Engineering (WSE 2014): . Paper presented at 10th Meeting of the Northern European Network for Wood Science & Engineering (WSE) 2014. Edinburgh Napier University
Åpne denne publikasjonen i ny fane eller vindu >>Improvement of a cytochemical method for localization of hydrogen peroxide and adaptation to furfurylated wood
2014 (engelsk)Inngår i: Proceedings of 10th Meeting of the Northern European Network for Wood Science & Engineering (WSE 2014), Edinburgh Napier University , 2014, , s. 180-186Konferansepaper, Publicerat paper (Fagfellevurdert)
sted, utgiver, år, opplag, sider
Edinburgh Napier University, 2014. s. 180-186
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-12363 (URN)16576 (Lokal ID)16576 (Arkivnummer)16576 (OAI)
Konferanse
10th Meeting of the Northern European Network for Wood Science & Engineering (WSE) 2014
Tilgjengelig fra: 2016-09-13 Laget: 2016-09-13 Sist oppdatert: 2018-08-15bibliografisk kontrollert
Ringman, R., Pilgård, A. & Richter, K. (2014). In vitro oxidative and enzymatic degradation of modified wood (ed.). In: The seventh European Conference on Wood Modification : Book of Abstracts: . Paper presented at The seventh European Conference on Wood Modification. Lisboa, Portugal. March 10-12, 2014 (pp. 36-39). , 6, Article ID 1.
Åpne denne publikasjonen i ny fane eller vindu >>In vitro oxidative and enzymatic degradation of modified wood
2014 (engelsk)Inngår i: The seventh European Conference on Wood Modification : Book of Abstracts, 2014, Vol. 6, s. 36-39, artikkel-id 1Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

Fungal cellulases have been shown to be less efficient in modified wood than in untreated wood (Lekounogou et al. 2008; Vena°s 2008). However, Verma and Mai (2010) showed that cellulase efficacy is partly restored in 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) treated wood by pre-treatment with Fenton's reagent, simulating the oxidative degradation phase in initial brown rot decay. In this study, we examined whether Fenton derived hydroxyl radicals (OH) and cellulases are able to cleave polysaccharides in furfurylated and acetylated wood and to what extent enzyme efficacy is increased by oxidative pre-treatment of these materials. The results show that fungal cellulases were able to degrade acetylated wood and that the cellulase efficacy was increased by oxidative pre-treatment by 20%, which is half of the increase in untreated wood. Furthermore, the results indicate that poly(furfuryl alcohol) is degraded by Fenton derived OH. This indicates a possible route for the eventual degradation of modified wood.

Serie
The International Wood Products Journal, ISSN 2042-6445
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-12431 (URN)10.1179/2042645314Y.0000000080 (DOI)2-s2.0-84923009248 (Scopus ID)19309 (Lokal ID)19309 (Arkivnummer)19309 (OAI)
Konferanse
The seventh European Conference on Wood Modification. Lisboa, Portugal. March 10-12, 2014
Tilgjengelig fra: 2016-09-13 Laget: 2016-09-13 Sist oppdatert: 2019-08-13bibliografisk kontrollert
Ringman, R., Pilgård, A., Brischke, C. & Richter, K. (2014). Mode of action of brown rot decay resistance in modified wood: a review (ed.). Holzforschung, 68(2), 239–246
Åpne denne publikasjonen i ny fane eller vindu >>Mode of action of brown rot decay resistance in modified wood: a review
2014 (engelsk)Inngår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 68, nr 2, s. 239–246-Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

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.

HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-6604 (URN)10.1515/hf-2013-0057 (DOI)2-s2.0-84900570147 (Scopus ID)15234 (Lokal ID)15234 (Arkivnummer)15234 (OAI)
Tilgjengelig fra: 2016-09-08 Laget: 2016-09-08 Sist oppdatert: 2019-08-08bibliografisk kontrollert
Ringman, R., Pilgård, A., Alfredsen, G., Goodell, B. & Richter, K. (2014). Possible targets of wood modification in brown rot degradation (ed.). In: Proceedings IRG Annual Meeting 2014 - IRG/WP 14: . Paper presented at IRG Annual Meeting 2014 - IRG/WP 14.
Åpne denne publikasjonen i ny fane eller vindu >>Possible targets of wood modification in brown rot degradation
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2014 (engelsk)Inngår i: Proceedings IRG Annual Meeting 2014 - IRG/WP 14, 2014, , s. 13Konferansepaper, Publicerat paper (Annet vitenskapelig)
Publisher
s. 13
Serie
PROCEEDINGS IRG ANNUAL MEETING, ISSN 2000-8953
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-12361 (URN)16548 (Lokal ID)16548 (Arkivnummer)16548 (OAI)
Konferanse
IRG Annual Meeting 2014 - IRG/WP 14
Merknad

IRG/WP 14-40676

Tilgjengelig fra: 2016-09-13 Laget: 2016-09-13 Sist oppdatert: 2018-08-15bibliografisk kontrollert
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-6208-8314
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