SOLID-STATE C-13 NMR-STUDY OF WOOD DEGRADED BY THE BROWN-ROT FUNGUS GLOEOPHYLLUM-TRABEUM

Blocks of Pinus koraiensis wood were degraded by Gloeophyllum trabeum and examined by solid-slate C-13 NMR spectroscopy, using proton spin relaxation editing and resolution enhancement. Chemical compositions were estimated from relative signal areas. There was no evidence for preferential degradation of the noncrystalline cellulose which accounted for about 4% by weight of the initial wood. Loss of partly ordered cellulose on crystal surfaces exceeded the loss of crystal-interior cellulose. The proportion of the monoclinic I beta crystalline form increased. These results were interpreted in terms of preferential degradation of crystallites that were relatively narrow and/or of the triclinic Icl form. The spectra showed evidence for loss of hemicelluloses, particularly those associated with relatively sharp NMR signals suggesting some degree of molecular ordering. There was no delectable loss of lignin.