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Two-step steam pretreatment of softwood with SO2 impregnation for ethanol production

Söderström, Johanna LU ; Pilcher, Linda LU ; Galbe, Mats LU and Zacchi, Guido LU (2002) 23rd Symposium on Biotechnology for Fuels and Chemicals In Applied Biochemistry and Biotechnology 98. p.5-21
Abstract
Two-step steam pretreatment of softwood was investigated with the aim of improving the enzymatic digestibility for ethanol production. In the first step, softwood was impregnated with SO2 and steam pretreated at different severities. The first step was performed at low severity to hydrolyze the hemicellulose and release the sugars into the solution. The combination of time and temperature that yielded the highest amount of hemicellulosic sugars in the solution was determined. In the second step, the washed solid material from the optimized first step was impregnated once more with SO2 and steam pretreated under more severe conditions to enhance the enzymatic digestibility. The investigated temperature range was between 180 and 220 C, and... (More)
Two-step steam pretreatment of softwood was investigated with the aim of improving the enzymatic digestibility for ethanol production. In the first step, softwood was impregnated with SO2 and steam pretreated at different severities. The first step was performed at low severity to hydrolyze the hemicellulose and release the sugars into the solution. The combination of time and temperature that yielded the highest amount of hemicellulosic sugars in the solution was determined. In the second step, the washed solid material from the optimized first step was impregnated once more with SO2 and steam pretreated under more severe conditions to enhance the enzymatic digestibility. The investigated temperature range was between 180 and 220 C, and the residence times were 2, 5 and 10 min. The effectiveness of pretreatment was assessed by both enzymatic hydrolysis of the solids and simultaneous saccharification and fermentation (SSF) of the whole slurry after the second pretreatment step, in the presence of antibiotics. For each pretreatment combination, the liquid fraction was fermented to determine any inhibiting effects. At low severity in the second pretreatment step, a high conversion of cellulose was obtained in the enzymatic hydrolysis step, and at a high severity a high conversion of cellulose was obtained in the second pretreatment step. This resulted in an overall yield of sugars that was nearly constant over a wide range of severity. Compared with the one-step steam pretreatment, the two-step steam pretreatment resulted in a higher yield of sugar and in a slightly higher yield of ethanol. The overall sugar yield, when assessed by enzymatic hydrolysis, reached 80%. In the SSF configuration, an overall ethanol yield of 69% was attained. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
spruce, enzymatic hydrolysis, fermentation, simultaneous saccharification and
in
Applied Biochemistry and Biotechnology
volume
98
pages
5 - 21
publisher
Humana Press
conference name
23rd Symposium on Biotechnology for Fuels and Chemicals
external identifiers
  • wos:000175257800003
  • scopus:0036240707
ISSN
0273-2289
1559-0291
DOI
10.1385/ABAB:98-100:1-9:5
language
English
LU publication?
yes
id
66f28ec2-639a-4fa6-b7e7-6d77f7d6463c (old id 339696)
date added to LUP
2007-11-14 13:15:16
date last changed
2017-10-22 03:33:02
@inproceedings{66f28ec2-639a-4fa6-b7e7-6d77f7d6463c,
  abstract     = {Two-step steam pretreatment of softwood was investigated with the aim of improving the enzymatic digestibility for ethanol production. In the first step, softwood was impregnated with SO2 and steam pretreated at different severities. The first step was performed at low severity to hydrolyze the hemicellulose and release the sugars into the solution. The combination of time and temperature that yielded the highest amount of hemicellulosic sugars in the solution was determined. In the second step, the washed solid material from the optimized first step was impregnated once more with SO2 and steam pretreated under more severe conditions to enhance the enzymatic digestibility. The investigated temperature range was between 180 and 220 C, and the residence times were 2, 5 and 10 min. The effectiveness of pretreatment was assessed by both enzymatic hydrolysis of the solids and simultaneous saccharification and fermentation (SSF) of the whole slurry after the second pretreatment step, in the presence of antibiotics. For each pretreatment combination, the liquid fraction was fermented to determine any inhibiting effects. At low severity in the second pretreatment step, a high conversion of cellulose was obtained in the enzymatic hydrolysis step, and at a high severity a high conversion of cellulose was obtained in the second pretreatment step. This resulted in an overall yield of sugars that was nearly constant over a wide range of severity. Compared with the one-step steam pretreatment, the two-step steam pretreatment resulted in a higher yield of sugar and in a slightly higher yield of ethanol. The overall sugar yield, when assessed by enzymatic hydrolysis, reached 80%. In the SSF configuration, an overall ethanol yield of 69% was attained.},
  author       = {Söderström, Johanna and Pilcher, Linda and Galbe, Mats and Zacchi, Guido},
  booktitle    = {Applied Biochemistry and Biotechnology},
  issn         = {0273-2289},
  keyword      = {spruce,enzymatic hydrolysis,fermentation,simultaneous saccharification and},
  language     = {eng},
  pages        = {5--21},
  publisher    = {Humana Press},
  title        = {Two-step steam pretreatment of softwood with SO2 impregnation for ethanol production},
  url          = {http://dx.doi.org/10.1385/ABAB:98-100:1-9:5},
  volume       = {98},
  year         = {2002},
}