Fractionation of Forest Residues of Douglas-fir for Fermentable Sugar Production by SPORL Pretreatment
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Douglas-fir (Pseudotsuga menziesii) forest residues were physically fractionated through sieving. The bark and wood were separated for large-sized fractions (>12.7 mm), and their contents were determined. The chemical compositions of the large fractions were calculated based on the contents and chemical compositions of the bark and wood. The chemical compositions of the fine fractions were analyzed. The bark and wood content in the fine fractions was calculated based on the measured glucan and lignin contents in each fraction. It was found that fractionation by particle/chip size can effectively fractionate bark and wood and therefore lignin from carbohydrates. The large-sized fractions (>12.7 mm) represent approximately 60 % of the collected forest residues but only contain approximately 37 % of the total bark and 35 % of the total ash, or a selectivity over bark and ash of 1.6 and 1.7, respectively. Pretreatment of forest residues by sulfite pretreatment to overcome recalcitrance of lignocelluloses and subsequent enzymatic hydrolysis revealed the presence of 14.3 % bark can reduce substrate enzymatic digestibilities (SED) 16 % compared with that from a bark-free sample. The SED of a bark is 41 % compared with 73 % for wood when pretreated under the same conditions. Separating pretreatment of bark from wood is beneficial for producing a more enzymatically digestible substrate. The results from the present study could have significant implications for harvesting forest residues.
KeywordsForest residues Size fractionation/sieving Bark Pretreatment Enzymatic hydrolysis/saccharification
This work, as part of the Northwest Advanced Renewables Alliance (NARA), was funded by the Agriculture and Food Research Initiative Competitive Grant no. 2011-68005-30416 from the USDA National Institute of Food and Agriculture (NIFA). We would also like to acknowledge Novozymes North America for their constant support by complementary providing cellulase enzymes. We would also like to thank Fred Matt of USDA Forest Products Laboratory for conducting detailed chemical composition analysis. The financial support from NIFA and the Chinese Scholarship Council made the visiting appointment of Zhang at the USDA Forest Products Laboratory possible.
- 4.Zhu JY, Zhuang XS (2012) Conceptual net energy output for biofuel production from lignocellulosic biomass through biorefining. Prog Energy Combust Sci 38(4). doi: 10.1016/j.pecs.2012.03.007
- 5.Koch P (1980) Harvesting energy chips from forest residues-some concepts for the southern pine region. General Technical Report SO-33. USDA Forest Service, Pineville, LAGoogle Scholar
- 12.Harkin JM, Rowe JW (1971) Bark and its possible use. Research Note FPL-091. USDA Forest Service, Madison, WI. pp 1–55Google Scholar
- 18.Wood TM, Bhat M (1988) Methods for measuring cellulase activities. In: Colowick SP, Kaplan NO (eds) Methods in enzymology, vol 160, Biomass (Part A, cellulose and hemicellulose). Academic, New York, pp 87–112Google Scholar
- 19.Perlack RD, Stokes BJ (2011) DOE. 2011. U.S. billion-ton update: biomass supply for a bioenergy and bioproducts industry. Oakridge National Laboratory, Oak RidgeGoogle Scholar
- 20.Murphy GE, Pilkerton SJ (2011) Seasonal impacts on bark loss for Douglas-fir and Ponderosa pine harvested on the Pacific Northwest Coast of the USA. Int J For Eng 22(1):35–41Google Scholar
- 24.Schowalter TD, Morrell JJ (2002) Nutritional quality of Douglas-fir wood: effect of vertical and horizontal position on nutrient levels. Wood Fiber Sci 34(1):158–164Google Scholar