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Effect of poly(ethylene glycol) on enzymatic hydrolysis and adsorption of cellulase enzymes to pretreated lignocellulose

Börjesson, Johan LU ; Engqvist, Martin; Sipos, Balint and Tjerneld, Folke LU (2007) In Enzyme and Microbial Technology 41(1-2). p.186-195
Abstract
There is a need to develop the enzymatic hydrolysis of cellulose for production of ethanol from biomass. In recent years the inhibitory effects of lignin in lignocellulosic substrates has been the focus of several studies. This points to the importance of understanding the interactions between cellulose degrading enzymes and lignin. Surface active substances have been shown to adsorb to lignin surfaces resulting in reduction of unproductive enzyme binding. It is essential to understand the surface properties of both enzymes and lignin to develop pretreatment methods, surface active additives and engineering of cellulose degrading enzyme systems. This study investigates the PEG-lignin interaction as well as interactions between lignin and... (More)
There is a need to develop the enzymatic hydrolysis of cellulose for production of ethanol from biomass. In recent years the inhibitory effects of lignin in lignocellulosic substrates has been the focus of several studies. This points to the importance of understanding the interactions between cellulose degrading enzymes and lignin. Surface active substances have been shown to adsorb to lignin surfaces resulting in reduction of unproductive enzyme binding. It is essential to understand the surface properties of both enzymes and lignin to develop pretreatment methods, surface active additives and engineering of cellulose degrading enzyme systems. This study investigates the PEG-lignin interaction as well as interactions between lignin and the enzyme modules of the Hypocrea jecorina (Trichoderma reesei) enzymes Cel7A and Cel7B. Interactions were monitored with C-14 labelled PEG 4000 and by measuring the enzymatic activity in solution. It was found that the dominating driving force of PEG adsorption on lignin is hydrophobic interaction. The effect of PEG addition on enzyme conversion of lignocellulose increased with higher temperature due to increased adsorption of PEG on lignin, thus resulting in a higher surface density of PEG on the surface. The hydrophobic adsorption of enzymes to lignin induces denaturation of enzymes on lignin surfaces. The addition of PEG to the enzyme hydrolysis at a temperature of 50 degrees C is suggested to hinder deactivation of enzymes by exclusion of enzymes from lignin surfaces. The adsorption of full-length Cel7B to lignin was stronger than for Cel7A. A more hydrophobic surface on the flat face of the cellulose binding module (CBM) together with an additional exposed aromatic residue on the rough face of Cel7B CBM compared to Cel7A CBM gives a higher affinity to lignin for the Cel7B enzyme. (c) 2007 Elsevier Inc. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
enzymatic, CBM, Hypocrea jecorina, adsorption, PEG, cellulase, hydrolysis, lignin
in
Enzyme and Microbial Technology
volume
41
issue
1-2
pages
186 - 195
publisher
Elsevier
external identifiers
  • wos:000247107700028
  • scopus:34248205049
ISSN
0141-0229
DOI
10.1016/j.enzmictec.2007.01.003
language
English
LU publication?
yes
id
32503615-7713-40b3-8a44-058c99050610 (old id 651092)
date added to LUP
2007-12-05 11:36:01
date last changed
2017-11-19 03:40:14
@article{32503615-7713-40b3-8a44-058c99050610,
  abstract     = {There is a need to develop the enzymatic hydrolysis of cellulose for production of ethanol from biomass. In recent years the inhibitory effects of lignin in lignocellulosic substrates has been the focus of several studies. This points to the importance of understanding the interactions between cellulose degrading enzymes and lignin. Surface active substances have been shown to adsorb to lignin surfaces resulting in reduction of unproductive enzyme binding. It is essential to understand the surface properties of both enzymes and lignin to develop pretreatment methods, surface active additives and engineering of cellulose degrading enzyme systems. This study investigates the PEG-lignin interaction as well as interactions between lignin and the enzyme modules of the Hypocrea jecorina (Trichoderma reesei) enzymes Cel7A and Cel7B. Interactions were monitored with C-14 labelled PEG 4000 and by measuring the enzymatic activity in solution. It was found that the dominating driving force of PEG adsorption on lignin is hydrophobic interaction. The effect of PEG addition on enzyme conversion of lignocellulose increased with higher temperature due to increased adsorption of PEG on lignin, thus resulting in a higher surface density of PEG on the surface. The hydrophobic adsorption of enzymes to lignin induces denaturation of enzymes on lignin surfaces. The addition of PEG to the enzyme hydrolysis at a temperature of 50 degrees C is suggested to hinder deactivation of enzymes by exclusion of enzymes from lignin surfaces. The adsorption of full-length Cel7B to lignin was stronger than for Cel7A. A more hydrophobic surface on the flat face of the cellulose binding module (CBM) together with an additional exposed aromatic residue on the rough face of Cel7B CBM compared to Cel7A CBM gives a higher affinity to lignin for the Cel7B enzyme. (c) 2007 Elsevier Inc. All rights reserved.},
  author       = {Börjesson, Johan and Engqvist, Martin and Sipos, Balint and Tjerneld, Folke},
  issn         = {0141-0229},
  keyword      = {enzymatic,CBM,Hypocrea jecorina,adsorption,PEG,cellulase,hydrolysis,lignin},
  language     = {eng},
  number       = {1-2},
  pages        = {186--195},
  publisher    = {Elsevier},
  series       = {Enzyme and Microbial Technology},
  title        = {Effect of poly(ethylene glycol) on enzymatic hydrolysis and adsorption of cellulase enzymes to pretreated lignocellulose},
  url          = {http://dx.doi.org/10.1016/j.enzmictec.2007.01.003},
  volume       = {41},
  year         = {2007},
}