p-Hydroxyphenyl:Guaiacyl:Syringyl Ratio of Lignin in Some Austral Hardwoods Estimated by CuO-Oxidation and Solid-State NMR

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Abstract
6 pages, 3 figures, 4 tables, 32 references.The white-rot fungus Ganoderma australe causes extensive decay of hardwood in Chilean rain forest, producing a delignified material used as cattle feed. Since lignin composition can influence the delignification efficiency, it was investigated by CuO alkaline degradation and solid-state NMR of wood. The lignin syringyl/guaiacyl ratio estimated by both techniques presented high values in the two woods, i.e., Eucryphia cordifolia and Nothofagus dombeyi, which showed the most selective delignification and the highest digestibility after fungal decay. On the other hand, a reduced S/G ratio was found in the Aextoxicon punctatum wood, which presented a low biodegradability. An additional peculiarity of the two former hardwoods is the relatively high yield of non-cinnamic p-hydroxyphenyl compounds after CuO alkaline degradation.This research has been supported by the Volkswagenwerk Foundation and the Spanish Biotec hnology Program (Grants Nº PBT85-10 and BIO88-0185).Peer reviewe