Use of 13C NMR, sorption and chemical analyses for characteristics of brown-rotted Scots pine

Abstract

To define the decomposition patterns of wood cell wall, three economically important brown-rot fungi, Coniophora puteana, Postia placenta, and Gloeophyllum trabeum were studied. Degraded Scots pine ( Pinus sylvestris L.) sapwood blocks were analysed using 13C NMR spectroscopy, chemical, and water vapor sorption methods. C. puteana caused the most wood decay (55%) after 50 days of exposure, while the destructive abilities of P. placenta and G. trabeum were 32 and 30%, respectively. Hemicellulose was removed preferably to cellulose, but the intensity of depletion depended on the fungus species rather than the mass loss. P. placenta and C. puteana removed 11.8 and 14.7% of the lignin, respectively, while G. trabeum removed 25.2%. The possible re-polymerization of lignin stopped any further lignin degradation during attack by C. puteana and P. placenta, while G. trabeum continued to degrade lignin until the end of the test. Removal of lignin metoxyl groups and formation of the reactive phenolic hydroxyl groups can be coupled to the reactions of Fenton reagents or other powerful oxidants in acidic conditions. Removal of hemicellulose and lignin (primarily methoxyl groups) will promote further access of fungal metabolites to cellulose fibers. A common regularity of the surface A accessible to water molecules and the losses of the wood weight was obtained. The mass hydrophilicity of sorbent a m in brown-rotted wood tended to decrease as the share of lignin increased.