Cellulases adsorb reversibly on biomass lignin

Demi T. Djajadi, Ville Pihlajaniemi, Jenni Rahikainen, Kristiina Kruus, Anne S. Meyer*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

31 Citations (Scopus)

Abstract

Adsorption of cellulases onto lignin is considered a major factor in retarding enzymatic cellulose degradation of lignocellulosic biomass. However, the adsorption mechanisms and kinetics are not well understood for individual types of cellulases. This study examines the binding affinity, kinetics of adsorption, and competition of four monocomponent cellulases of Trichoderma reesei during adsorption onto lignin. TrCel7A, TrCel6A, TrCel7B, and TrCel5A were radiolabeled for adsorption experiments on lignin-rich residues (LRRs) isolated from hydrothermally pretreated spruce (L-HPS) and wheat straw (L-HPWS), respectively. On the basis of adsorption isotherms fitted to the Langmuir model, the ranking of binding affinities was TrCel5A > TrCel6A > TrCel7B > TrCel7A on both types of LRRs. The enzymes had a higher affinity to the L-HPS than to the L-HPWS. Adsorption experiments with dilution after 1 and 24 hr and kinetic modeling were performed to quantify any irreversible binding over time. Models with reversible binding parameters fitted well and can explain the results obtained. The adsorption constants obtained from the reversible models agreed with the fitted Langmuir isotherms and suggested that reversible adsorption–desorption existed at equilibrium. Competitive binding experiments showed that individual types of cellulases competed for binding sites on the lignin and the adsorption data fitted the Langmuir adsorption model. Overall, the data strongly indicate that the adsorption of cellulases onto lignin is reversible and the findings have implications for the development of more efficient cellulose degrading enzymes.

Original languageEnglish
Pages (from-to)2869-2880
Number of pages12
JournalBiotechnology and Bioengineering
Volume115
Issue number12
DOIs
Publication statusPublished - 1 Dec 2018
MoE publication typeA1 Journal article-refereed

Keywords

  • adsorption
  • biomass
  • cellulase
  • competition
  • lignin
  • reversible

Fingerprint

Dive into the research topics of 'Cellulases adsorb reversibly on biomass lignin'. Together they form a unique fingerprint.

Cite this