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Mechanism of surfactant effect in enzymatic hydrolysis of lignocellulose

Eriksson, Torny LU ; Börjesson, Johan LU and Tjerneld, Folke LU (2002) In Enzyme and Microbial Technology 31(3). p.353-364
Abstract
Lignocellulose is a potential substrate for ethanol production. However, high cellulose conversion requires high enzyme loading, which makes the process less economically feasible. Addition of surfactants to enzymatic hydrolysis of lignocellulose increases the conversion of cellulose into soluble sugars. The mechanism is not known for the increase of lignocellulose hydrolysis by surfactant addition, therefore, experiments were designed to explore mechanisms of surfactant effects. A number of surfactants were screened for their ability to improve enzymatic hydrolysis of steam-pretreated spruce (SPS). Non-ionic surfactants were found to be the most effective. Studies of adsorption of the dominating cellulase of Trichoderma reesei, Cel7A... (More)
Lignocellulose is a potential substrate for ethanol production. However, high cellulose conversion requires high enzyme loading, which makes the process less economically feasible. Addition of surfactants to enzymatic hydrolysis of lignocellulose increases the conversion of cellulose into soluble sugars. The mechanism is not known for the increase of lignocellulose hydrolysis by surfactant addition, therefore, experiments were designed to explore mechanisms of surfactant effects. A number of surfactants were screened for their ability to improve enzymatic hydrolysis of steam-pretreated spruce (SPS). Non-ionic surfactants were found to be the most effective. Studies of adsorption of the dominating cellulase of Trichoderma reesei, Cel7A (CBHI), during hydrolysis showed that the anionic and non-ionic surfactants reduced enzyme adsorption to the lignocellulose substrate. The approximate reduction of enzyme adsorption was from 90% adsorbed enzyme to 80% with surfactant addition. Cellulase stability in the presence of surfactants was studied by activity and fluorescence measurements. Surfactants were shown to have only a weak effect on cellulase temperature stability. Our conclusions from studies of lignocellulose and delignified substrates are that the improved conversion of lignocellulose with surfactant can be explained by the reduction of the unproductive enzyme adsorption to the lignin part of the substrate. This is due to hydrophobic interaction of surfactant with lignin on the lignocellulose surface, which releases unspecifically bound enzyme. A new approach with mixed charged and non-ionic surfactants has been introduced to further improve the positive effect of the surfactant addition. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cellulase, Cellulose, Lignocellulose, Enzyme hydrolysis, Surfactant, Trichoderma reesei, Adsorption, Cel7A
in
Enzyme and Microbial Technology
volume
31
issue
3
pages
353 - 364
publisher
Elsevier
external identifiers
  • wos:000177498900021
  • scopus:0037008410
ISSN
0141-0229
DOI
10.1016/S0141-0229(02)00134-5
language
English
LU publication?
yes
id
9c511c1c-d9b5-4aef-96c0-d85f8433af24 (old id 124786)
date added to LUP
2007-07-05 08:35:30
date last changed
2017-12-10 03:41:59
@article{9c511c1c-d9b5-4aef-96c0-d85f8433af24,
  abstract     = {Lignocellulose is a potential substrate for ethanol production. However, high cellulose conversion requires high enzyme loading, which makes the process less economically feasible. Addition of surfactants to enzymatic hydrolysis of lignocellulose increases the conversion of cellulose into soluble sugars. The mechanism is not known for the increase of lignocellulose hydrolysis by surfactant addition, therefore, experiments were designed to explore mechanisms of surfactant effects. A number of surfactants were screened for their ability to improve enzymatic hydrolysis of steam-pretreated spruce (SPS). Non-ionic surfactants were found to be the most effective. Studies of adsorption of the dominating cellulase of Trichoderma reesei, Cel7A (CBHI), during hydrolysis showed that the anionic and non-ionic surfactants reduced enzyme adsorption to the lignocellulose substrate. The approximate reduction of enzyme adsorption was from 90% adsorbed enzyme to 80% with surfactant addition. Cellulase stability in the presence of surfactants was studied by activity and fluorescence measurements. Surfactants were shown to have only a weak effect on cellulase temperature stability. Our conclusions from studies of lignocellulose and delignified substrates are that the improved conversion of lignocellulose with surfactant can be explained by the reduction of the unproductive enzyme adsorption to the lignin part of the substrate. This is due to hydrophobic interaction of surfactant with lignin on the lignocellulose surface, which releases unspecifically bound enzyme. A new approach with mixed charged and non-ionic surfactants has been introduced to further improve the positive effect of the surfactant addition.},
  author       = {Eriksson, Torny and Börjesson, Johan and Tjerneld, Folke},
  issn         = {0141-0229},
  keyword      = {Cellulase,Cellulose,Lignocellulose,Enzyme hydrolysis,Surfactant,Trichoderma reesei,Adsorption,Cel7A},
  language     = {eng},
  number       = {3},
  pages        = {353--364},
  publisher    = {Elsevier},
  series       = {Enzyme and Microbial Technology},
  title        = {Mechanism of surfactant effect in enzymatic hydrolysis of lignocellulose},
  url          = {http://dx.doi.org/10.1016/S0141-0229(02)00134-5},
  volume       = {31},
  year         = {2002},
}