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Title: Revealing the molecular structural transformation of hardwood and softwood in dilute acid flowthrough pretreatment

To understand better the intrinsic recalcitrance of lignocellulosic biomass, the main hurdle to its efficient deconstruction, the effects of dilute acid flowthrough pretreatment on the dissolution chemistry of hemicellulose, cellulose, and lignin for both hardwood (e.g., poplar wood) and softwood (e.g., lodgepole pine wood) were investigated at temperatures of 200 to 270 °C and a flow rate of 25 mL/min with 0.05% (w/w) H 2SO 4. Results suggested that the softwood cellulose was more readily degraded into monomeric sugars than that of hardwood under same pretreatment conditions. However, while the hardwood lignin was completely removed into hydrolysate, ~30% of the softwood lignin remained as solid residues under identical conditions, which was plausibly caused by vigorous C5-active recondensation reactions (C–C5). As a result, effects of molecular structural features (i.e., lignin molecular weight, cellulose crystallinity, and condensed lignin structures) on the recalcitrance of hardwood and softwood to dilute acid pretreatment were identified for the first time in this study, providing important insights to establish the effective biomass pretreatment.
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [3] ;  [1]
  1. Washington State Univ., Pullman, WA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. (United States)
  4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
ACS Sustainable Chemistry & Engineering
Additional Journal Information:
Journal Volume: 4; Journal Issue: 12; Journal ID: ISSN 2168-0485
American Chemical Society (ACS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; flowthrough pretreatment; hardwood; lignin chemistry; lignin recondensation; softwood
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1376570