Title:
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Fractionation of Wheat Straw by Prehydrolysis, Organosolv Delignification and Enzymatic Hydrolysis for Production of Sugars and Lignin
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Author(s):
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Published by:
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Publication date:
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ECN
Biomass & Energy Efficiency
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2-2-2012
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ECN report number:
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Document type:
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ECN-W--12-004
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Article (scientific)
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Number of pages:
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12
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Published in: Bioresource Technology (Elsevier), , 2012, Vol.114, p.389-398.
Abstract:
Wheat straw was fractionated using a three-step biorefining approach: (1) aqueous pretreatment for hemicellulose prehydrolysis into sugars, (2) organosolv delignification, and (3) enzymatic cellulose hydrolysis into glucose. Prehydrolysis was applied to avoid degradation of hemicellulose sugars during organosolv delignification. Maximum xylose yield obtained was 67% or 0.17 kg/kg straw (prehydrolysis: 175 _C, 30 min, 20 mM H2SO4) compared to 4% in case of organosolv without prehydrolysis (organosolv: 200 _C, 60 min, 60% w/w aqueous ethanol). Prehydrolysis was found to reduce the lignin yield by organosolv delignification due to the formation of ‘pseudo-lignin’ and lignin recondensation during prehydrolysis. This reduction could partly be compensated by increasing the temperature of the organosolv delignification step. Prehydrolysis substantially improved the enzymatic cellulose digestibility from 49% after organosolv without prehydrolysis to 80% (20 FPU/g substrate). Increasing the organosolv delignification temperature to 220 _C resulted in a maximum enzymatic glucose yield of 93% or 0.36 kg/kg straw.
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