Evaluation of forestry biomass quality for the production of second-generation biofuels

摘要: Different classes of wooden material were analysed as to their chemical composition, especially as to the content of fermentable sugars: softwood and hardwood unbarked wood, SRC, VSRC and different grades of forest chips. High hexose contents were preferably found in unbarked softwoods, which presented up to 4% more C6 sugars than unbarked hardwoods. However, some hardwood species, such as eucalyptus and poplar clones, presented very high hexose content values. Short rotation coppices present just slightly lower average hexose content compared to mature wood, but very short rotation coppices are poorer in hexoses, by 3% on the average. The hexose content of forest chips is significantly affected by the non-wood fractions. On the average, the gap between mature unbarked wood and forest chips is of 5% for hardwoods and of 8% for softwoods. Finally, if upgrading of pentoses by fermentation into bioethanol is possible, hardwoods seem to be a good raw material, as the presence of C5 sugars is considerably more important than in softwoods.