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Recirculation of process streams in fuel ethanol production from softwood based on simultaneous saccharification and fermentation

Alkasrawi, Malek LU ; Galbe, Mats LU and Zacchi, Guido LU (2002) 23rd Symposium on Biotechnology for Fuels and Chemical In Applied Biochemistry and Biotechnology 98. p.849-861
Abstract
The effect of process stream recirculation on ethanol production from steam- pretreated softwood based on simultaneous saccharification and fermentation (SSF) was investigated for two process configurations. In the first configuration, a part of the stillage stream after distillation was recycled and, in the second configuration, the liquid after SSF was recycled. The aim was to minimize the energy consumption in the distillation of the fermentation broth and in the evaporation of the stillage, as well as the use of fresh water. However, recirculation leads to an increased concentration of nonvolatiles in the first configuration, and of both volatiles and nonvolatiles in the second configuration. These substances might be inhibitory to the... (More)
The effect of process stream recirculation on ethanol production from steam- pretreated softwood based on simultaneous saccharification and fermentation (SSF) was investigated for two process configurations. In the first configuration, a part of the stillage stream after distillation was recycled and, in the second configuration, the liquid after SSF was recycled. The aim was to minimize the energy consumption in the distillation of the fermentation broth and in the evaporation of the stillage, as well as the use of fresh water. However, recirculation leads to an increased concentration of nonvolatiles in the first configuration, and of both volatiles and nonvolatiles in the second configuration. These substances might be inhibitory to the enzymes and the yeast in SSF. When 60% of the fresh water was replaced by stillage, the ethanol yield and the productivity were the same as for the configuration without recirculation. The ethanol production cost was reduced by 17%. In the second configuration, up to 40% of the fresh water could be replaced without affecting the final ethanol yield, although the initial ethanol productivity decreased. The ethanol production cost was reduced by 12%. At higher degrees of recirculation,fermentation was clearly inhibited, resulting in a decrease in ethanol yield while hydrolysis seemed unaffected. (Less)
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author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
recirculation, simultaneous saccharification and fermentation, softwood, inhibition, ethanol
in
Applied Biochemistry and Biotechnology
volume
98
pages
849 - 861
publisher
Humana Press
conference name
23rd Symposium on Biotechnology for Fuels and Chemical
external identifiers
  • wos:000175257800073
  • scopus:0036237212
ISSN
1559-0291
0273-2289
language
English
LU publication?
yes
id
9690a751-84a7-475d-8d3d-f34a1e829beb (old id 339719)
date added to LUP
2007-08-06 14:44:14
date last changed
2017-08-06 03:32:27
@inproceedings{9690a751-84a7-475d-8d3d-f34a1e829beb,
  abstract     = {The effect of process stream recirculation on ethanol production from steam- pretreated softwood based on simultaneous saccharification and fermentation (SSF) was investigated for two process configurations. In the first configuration, a part of the stillage stream after distillation was recycled and, in the second configuration, the liquid after SSF was recycled. The aim was to minimize the energy consumption in the distillation of the fermentation broth and in the evaporation of the stillage, as well as the use of fresh water. However, recirculation leads to an increased concentration of nonvolatiles in the first configuration, and of both volatiles and nonvolatiles in the second configuration. These substances might be inhibitory to the enzymes and the yeast in SSF. When 60% of the fresh water was replaced by stillage, the ethanol yield and the productivity were the same as for the configuration without recirculation. The ethanol production cost was reduced by 17%. In the second configuration, up to 40% of the fresh water could be replaced without affecting the final ethanol yield, although the initial ethanol productivity decreased. The ethanol production cost was reduced by 12%. At higher degrees of recirculation,fermentation was clearly inhibited, resulting in a decrease in ethanol yield while hydrolysis seemed unaffected.},
  author       = {Alkasrawi, Malek and Galbe, Mats and Zacchi, Guido},
  booktitle    = {Applied Biochemistry and Biotechnology},
  issn         = {1559-0291},
  keyword      = {recirculation,simultaneous saccharification and fermentation,softwood,inhibition,ethanol},
  language     = {eng},
  pages        = {849--861},
  publisher    = {Humana Press},
  title        = {Recirculation of process streams in fuel ethanol production from softwood based on simultaneous saccharification and fermentation},
  volume       = {98},
  year         = {2002},
}