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

To define the decomposition patterns of wood cell wall, three economically important brown-rot fungi, Coniophora puteana, Postia placenta, and Gloeoph yllum trabeum were studied. Degraded Scots pine (Pinus sylvestris L.) sapwo od blocks were analysed using C-13 NMR spectroscopy, chemical, and water va por sorption methods. C. puteana caused the most wood decay (55%) after 50 days of exposure, while the destructive abilities of P. placenta and G. tra beum were 32 and 30%, respectively. Hemicellulose was removed preferably to cellulose, but the intensity of depletion depended on the fungus species r ather 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 a ttack 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 form ation of the reactive phenolic hydroxyl groups can be coupled to the reacti ons of Fenton reagents or other powerful oxidants in acidic conditions. Rem oval of hemicellulose and lignin (primarily methoxyl groups) will promote f urther access of fungal metabolites to cellulose fibers. A common regularit y of the surface A accessible to water molecules and the losses of the wood weight was obtained. The mass hydrophilicity of sorbent a, in brown-rotted wood tended to decrease as the share of lignin increased. (C) 2001 Elsevie r Science Ltd. All rights reserved.