Biochemical Conversion of Torrefied Norway Spruce After Pretreatment with Acid or Ionic Liquid

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• 作者：Monica Normark ; Linda Pommer ; John Gräsvik ; Mattias Hedenström…
• 关键词：Torrefaction ; Wood ; Acid pretreatment ; Ionic liquid ; Enzymatic hydrolysis
• 刊名：BioEnergy Research
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：9
• 期：1
• 页码：355-368
• 全文大小：2,055 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Biomaterials
  Biochemical Engineering
  Bioorganic Chemistry
  
• 出版者：Springer New York
• ISSN：1939-1242

文摘

The chemical effects of torrefaction and the possibility to combine torrefaction with biochemical conversion were explored in experiments with five preparations of wood of Norway spruce that had been torrefied using different degrees of severity. Compositional analysis and analyses using solid-state CP/MAS 13C NMR, Fourier-transform infrared (FTIR) spectroscopy, and Py-GC/MS showed small gradual changes, such as decreased hemicellulosic content and increased Klason lignin value, for torrefaction conditions in the range from 260 °C and 8 min up to 310 °C and 8 min. The most severe torrefaction conditions (310 °C, 25 min) resulted in substantial loss of glucan and further increase of the Klason lignin value, which was attributed to conversion of carbohydrate to pseudo-lignin. Even mild torrefaction conditions led to decreased susceptibility to enzymatic hydrolysis of cellulose, a state which was not changed by pretreatment with sulfuric acid. Pretreatment with the ionic liquid (IL) 1-butyl-3-methylimidazolium acetate overcame the additional recalcitrance caused by torrefaction, and the glucose yields after 72 h of enzymatic hydrolysis of wood torrefied at 260 °C for 8 min and at 285 °C for 16.5 min were as high as that of IL-pretreated non-torrefied spruce wood. Compared to IL-pretreated non-torrefied reference wood, the glucose production rates after 2 h of enzymatic hydrolysis of IL-pretreated wood torrefied at 260 °C for 8 min and at 285 °C for 16.5 min were 63 and 40 % higher, respectively. The findings offer increased understanding of the effects of torrefaction and indicate that mild torrefaction is compatible with biochemical conversion after pretreatment with alternative solvents that disrupt pseudo-lignin-containing lignocellulose.