Biorefining: the role of endoglucanases in refining of cellulose fibers

Martin Nagl, Oskar Haske-Cornelius, Lukas Skopek, Alessandro Pellis, Wolfgang Bauer, Gibson Stephen Nyanhongo*, Georg Guebitz

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

With an annual production of more than 400 million tons, paper is the main product of the largest biorefinery process industrially implemented. Enzymes have been used for pulp refining to dramatically reduce energy consumption. However, exact mechanisms related to the individual enzymes are hardly understood. Yet, this knowledge would be important to predict enzyme performance in industrial processes. Three commercial refining enzyme formulations showed different endoglucanase (1.25 nkat mg−1–13.7 nkat mg−1), β-glucosidase (0.57 nkat mg−1–1.34 nkat mg−1) and xylanase activities (1.78 nkat ml−1–62.1 nkat mg−1) on model substrates. Additionally, distinct amounts of reducing sugars from hardwood sulfate pulp were released. Endoglucases were purified from each formulation by using hydrophobic interaction and anion exchange chromatography and showed molecular weights from 20 to 55 kDa and specific activities ranging between 3.11 and 26.3 nkat mg−1 according to endoglucanase specific derivatized cellopentaose (CellG5). Refining trials of hardwood sulfate pulp were conducted using a PFI laboratory mill and fiber properties such as degree of refining or fiber length and properties of formed sheets like tensile index were monitored. Thereby, enzymes were dosed based on identical endoglucanase activity on CellG5. Enzyme formulations and purified endoglucanases led to an increase of the degree of refining of up to 47.9 [°SR] at 6000 PFI revolutions while the tensile index was improved by up to 76.0 Nm g−1. In summary, refining effects can be primarily attributed to endoglucanases indicating activity on CellG5 being a suitable parameter for enzyme dosing.

Original languageEnglish
Pages (from-to)7633-7650
Number of pages18
JournalCellulose
Volume28
Issue number12
Early online date24 Jun 2021
DOIs
Publication statusPublished - Aug 2021

Keywords

  • CellG5
  • Cellulase
  • Cellulose fiber
  • Endoglucanase
  • Pulp
  • Refining

ASJC Scopus subject areas

  • Polymers and Plastics
  • Materials Science (miscellaneous)

Fields of Expertise

  • Advanced Materials Science
  • Sustainable Systems

Cooperations

  • NAWI Graz

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