Hydrothermal pretreatment of water-extracted and aqueous ethanol-extracted quinoa stalks for enzymatic saccharification of cellulose

Cristhian Carrasco, Leif J. Jönsson, Carlos Martín

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Auto-catalyzed hydrothermal pretreatment (A-HTP) and sulfuric-acid-catalyzed hydrothermal pretreatment (SA-HTP) were applied to quinoa stalks in order to reduce their recalcitrance towards enzymatic saccharification. Prior to pretreatment, quinoa stalks were extracted with either water or a 50:50 (v/v) ethanol–water mixture for removing saponins. Extraction with water or aqueous ethanol, respectively, led to removal of 52 and 75% (w/w) of the saponins contained in the raw material. Preliminary extraction of quinoa stalks allowed for a lower overall severity during pretreatment, and it led to an increase of glucan recovery in the pretreated solids (above 90%) compared with that of non-extracted quinoa stalks (73–74%). Furthermore, preliminary extraction resulted in enhanced hydrolysis of hemicelluloses and lower by-product formation during pretreatment. The enhancement of hemicelluloses hydrolysis by pre-extraction was more noticeable for SA-HTP than for A-HTP. As a result of the pretreatment, glucan susceptibility towards enzymatic hydrolysis was remarkably improved, and the overall conversion values were higher for the pre-extracted materials (up to 83%) than for the non-extracted ones (64–69%). Higher overall conversion was achieved for the aqueous ethanol-extracted quinoa stalks (72–83%) than for the water-extracted material (65–74%).

Original languageEnglish
Article number4102
JournalEnergies
Volume14
Issue number14
DOIs
StatePublished - 2 Jul 2021

Bibliographical note

Funding Information:
Funding: This research was funded by the Swedish Research Council (2016-05822) and the Bio4Energy research environment (www.bio4energy.se, accessed on 2 July 2021).

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Keywords

  • Enzymatic saccharification
  • Extraction
  • Hydrothermal pretreatment
  • Quinoa stalks
  • Saponins

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