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Enhanced enzymatic conversion of softwood lignocellulose by poly(ethylene glycol) addition

Börjesson, Johan LU ; Peterson Wulff, Ragna LU and Tjerneld, Folke LU (2007) In Enzyme and Microbial Technology 40(4). p.754-762
Abstract
Ethanol production from lignocellulose has great potential and is an important step in changing fuel consumption to a more environmentally friendly alternative. Lignocellulose is a large source of biomass. However, with lignocellulose and softwood lingocellulose in particular, high conversion of cellulose into fermentable sugars requires large amounts of enzymes. Addition of surfactants is known to increase the enzymatic conversion and decrease the amount of enzymes needed. Surfactants and polymers with various amount of ethylene oxide (EO) content were used to study the conversion of steam-pretreated spruce lignocellulose. Increasing conversion was obtained with longer EO chains on the non-ionic surfactants. Similar results were obtained... (More)
Ethanol production from lignocellulose has great potential and is an important step in changing fuel consumption to a more environmentally friendly alternative. Lignocellulose is a large source of biomass. However, with lignocellulose and softwood lingocellulose in particular, high conversion of cellulose into fermentable sugars requires large amounts of enzymes. Addition of surfactants is known to increase the enzymatic conversion and decrease the amount of enzymes needed. Surfactants and polymers with various amount of ethylene oxide (EO) content were used to study the conversion of steam-pretreated spruce lignocellulose. Increasing conversion was obtained with longer EO chains on the non-ionic surfactants. Similar results were obtained by using only the hydrophilic part of the surfactant, i.e. by addition of ethylene oxide polymers such as poly(ethylene glycol) (PEG) to the hydrolysis mixture. Interactions of enzymes and PEG with substrate was monitored with C-14-labeled PEG 4000 and H-3-labeled Cel7A (CBH I), the dominating cellulase from Trichoderma reesei. Addition of PEG to enzyme hydrolysis of lignocellulose increased the conversion from 42% without addition to 78% in 16 h. Adsorption of Cel7A decreased from 81 to 59%. No effect of PEG was seen on a delignified substrate. By addition of PEG it was possible to perform hydrolysis at 50 degrees C leading to both high cellulose conversion (80%) and shorter process time (48 h). Two different interactions are proposed in PEG adsorption on lignocellulose, hydrogen bonding and hydrophobic interactions. Our conclusions from experiments on lignocellulose and delignified substrate are that EO containing surfactants and polymers, such as PEG, bind to lignin by hydrophobic interaction and hydrogen bonding and reduce the unproductive binding of enzymes. (c) 2006 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
Trichoderma reesei, PEG, surfactants, lignin, lignocellulose, cellulase, cellulose, adsorption, Cel7A, enzymatic hydrolysis
in
Enzyme and Microbial Technology
volume
40
issue
4
pages
754 - 762
publisher
Elsevier
external identifiers
  • wos:000245015600036
  • scopus:33847325663
ISSN
0141-0229
DOI
10.1016/j.enzmictec.2006.06.006
language
English
LU publication?
yes
id
e7f17f94-2fcc-4f51-98cf-af5c1831af03 (old id 669831)
date added to LUP
2007-12-05 11:37:11
date last changed
2017-11-19 03:37:52
@article{e7f17f94-2fcc-4f51-98cf-af5c1831af03,
  abstract     = {Ethanol production from lignocellulose has great potential and is an important step in changing fuel consumption to a more environmentally friendly alternative. Lignocellulose is a large source of biomass. However, with lignocellulose and softwood lingocellulose in particular, high conversion of cellulose into fermentable sugars requires large amounts of enzymes. Addition of surfactants is known to increase the enzymatic conversion and decrease the amount of enzymes needed. Surfactants and polymers with various amount of ethylene oxide (EO) content were used to study the conversion of steam-pretreated spruce lignocellulose. Increasing conversion was obtained with longer EO chains on the non-ionic surfactants. Similar results were obtained by using only the hydrophilic part of the surfactant, i.e. by addition of ethylene oxide polymers such as poly(ethylene glycol) (PEG) to the hydrolysis mixture. Interactions of enzymes and PEG with substrate was monitored with C-14-labeled PEG 4000 and H-3-labeled Cel7A (CBH I), the dominating cellulase from Trichoderma reesei. Addition of PEG to enzyme hydrolysis of lignocellulose increased the conversion from 42% without addition to 78% in 16 h. Adsorption of Cel7A decreased from 81 to 59%. No effect of PEG was seen on a delignified substrate. By addition of PEG it was possible to perform hydrolysis at 50 degrees C leading to both high cellulose conversion (80%) and shorter process time (48 h). Two different interactions are proposed in PEG adsorption on lignocellulose, hydrogen bonding and hydrophobic interactions. Our conclusions from experiments on lignocellulose and delignified substrate are that EO containing surfactants and polymers, such as PEG, bind to lignin by hydrophobic interaction and hydrogen bonding and reduce the unproductive binding of enzymes. (c) 2006 Elsevier Inc. All rights reserved.},
  author       = {Börjesson, Johan and Peterson Wulff, Ragna and Tjerneld, Folke},
  issn         = {0141-0229},
  keyword      = {Trichoderma reesei,PEG,surfactants,lignin,lignocellulose,cellulase,cellulose,adsorption,Cel7A,enzymatic hydrolysis},
  language     = {eng},
  number       = {4},
  pages        = {754--762},
  publisher    = {Elsevier},
  series       = {Enzyme and Microbial Technology},
  title        = {Enhanced enzymatic conversion of softwood lignocellulose by poly(ethylene glycol) addition},
  url          = {http://dx.doi.org/10.1016/j.enzmictec.2006.06.006},
  volume       = {40},
  year         = {2007},
}