Imidazole: Prospect Solvent for Lignocellulosic Biomass Fractionation and Delignification

A R C Morais, J V Pinto, D Nunes, Luísa B. Roseiro, M C Oliveira, E Fortunato, Rafał Bogel-Łukasik

Research output: Contribution to journalArticlepeer-review

66 Citations (Scopus)


The future widespread production of biomass-derived fuels, chemicals, and materials requires cost-effective processing of sustainable feedstock. The use of imidazole as a solvent for biomass creates a novel approach that helps to accomplish this idea in a green fashion. This work proposes imidazole as a novel solvent for wheat straw pretreatment, which allowed the production of cellulose- and hemicellulose-rich fractions and added-value products from depolymerization of lignin. Various temperatures (110, 140, and 170 °C) and processing times (1, 2, and 4 h) of pretreatment were investigated. Both cellulose and hemicellulose recovery were highly dependent on reaction temperature. The best result for the recovery of cellulose-rich material was obtained at 170 °C for 2 h, achieving 62.4% w·w-1, whereas native wheat straw is composed by only 38.8% w·w-1 cellulose. For the same conditions, optimal results were also obtained regarding the enzymatic hydrolysis yield (99.3% w·w-1 glucan to glucose yield) in cellulose-rich material. This result was possible to be obtained due to morphological and structural changes in cellulose-rich materials accompanied by extensive delignification (up to 92%). The presence of added-value phenolic compounds in recovered imidazole was analyzed by capillary electrophoresis and HPLC-MS. Vanillin and other lignin-based products were identified. Finally, the high purity of recovered imidazole was demonstrated by 1H and 13C NMR.

Original languageEnglish
Pages (from-to)1643-1652
Number of pages10
Issue number3
Publication statusPublished - 7 Mar 2016


  • Biorefinery
  • Crystallinity
  • Delignification
  • Enzymatic hydrolysis
  • Green solvent
  • Imidazole
  • Lignocellulose
  • Pretreatment


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