Impact of Dilute Sulfuric Acid, Ammonium Hydroxide, and Ionic Liquid Pretreatments on the Fractionation and Characterization of Engineered Switchgrass

Enshi Liu, Lalitendu Das, Bingyu Zhao, Mark Crocker, Jian Shi

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Improving plant characteristics for better environmental resilience and more cost-effective transformation to fuels and chemicals is one of the focus areas in biomass feedstock development. In order to bridge lignin engineering and conversion technologies, this study aimed to fractionate and characterize lignin streams from wild-type and engineered switchgrass using three different pretreatment methods, i.e., dilute sulfuric acid (DA), ammonium hydroxide (AH), and aqueous ionic liquid (IL). Results demonstrate the low lignin content and high S/G ratio switchgrass mutant (4CL) was more susceptible to pretreatment and subsequently more digestible by enzymes as compared to wild-type switchgrass and AtLOV1 mutant. In addition, when compared to DA and AH pretreatment, aqueous IL (cholinium lysinate) was demostrated to be an efficient lignin solvent, as indicated by the high (> 80%) lignin solubility and reduced lignin molecular weight. FTIR and differential scanning calorimetry measurements suggest that pretreatment chemistry greatly influenced the structural and compositional changes and thermal properties of the pretreated switchgrass and recovered lignin-rich streams. The comparative data obtained from this work deepen our understanding of how lignin modification impacts the fractionation and properties of biomass feedstocks.

Original languageEnglish
Pages (from-to)1079-1093
Number of pages15
JournalBioenergy Research
Issue number4
StatePublished - Dec 1 2017

Bibliographical note

Funding Information:
Funding Information The authors acknowledge the National Science Foundation under Cooperative Agreement No. 1355438 and 1632854 and the National Institute of Food and Agriculture, US Department of Agriculture, Hatch-Multistate project under accession number 1003563 for supporting this research. The Virginia Tech work was partially supported by USDA-NIFA Grant Number 2011-67009-30133 and by a Virginia Tech CALS integrative grant and the Virginia Agricultural Experiment Station (VA135872).

Publisher Copyright:
© 2017, Springer Science+Business Media, LLC.


  • Biofuels
  • Genetic modification
  • Lignin
  • Pretreatment
  • Switchgrass

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Agronomy and Crop Science
  • Energy (miscellaneous)


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