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Influence of enzyme loading and physical parameters on the enzymatic hydrolysis of steam-pretreated softwood

Tengborg, C; Galbe, Mats LU and Zacchi, Guido LU (2001) In Biotechnology Progress 17(1). p.110-117
Abstract
Softwood is an interesting raw material for the production of fuel ethanol as a result of its high content of hexoses, and it has attracted attention especially in the Northern hemisphere. However, the enzymatic hydrolysis of softwood is not sufficiently efficient for the complete conversion of cellulose to glucose. Since an improvement in the glucose yield is of great importance for the overall economy of the process, the influence of various parameters on the cellulose conversion of steam-pretreated spruce has been investigated. The addition of beta -glucosidase up to 50 IU g(-1) cellulose to the enzymatic hydrolysis process resulted in increased cellulose conversion at a cellulase loading up to 48 FPU g(-1) cellulose. Despite very high... (More)
Softwood is an interesting raw material for the production of fuel ethanol as a result of its high content of hexoses, and it has attracted attention especially in the Northern hemisphere. However, the enzymatic hydrolysis of softwood is not sufficiently efficient for the complete conversion of cellulose to glucose. Since an improvement in the glucose yield is of great importance for the overall economy of the process, the influence of various parameters on the cellulose conversion of steam-pretreated spruce has been investigated. The addition of beta -glucosidase up to 50 IU g(-1) cellulose to the enzymatic hydrolysis process resulted in increased cellulose conversion at a cellulase loading up to 48 FPU g(-1) cellulose. Despite very high enzyme loading (120 FPU g(-1) cellulose) only about 50% of the cellulose in steam-pretreated spruce was converted to glucose when all of the material following pretreatment was used in the hydrolysis step. The influence of temperature, residence time, and pH were investigated for washed pretreated spruce at a dry matter (DM) content of 5% and a cellulase activity of 18.5 FPU g(-1) cellulose. The optimal temperature was found to be dependent on both residence time and pH, and the maximum degree of cellulose conversion, 69.2%, was obtained at 38 degreesC and pH 4.9 for a residence time of 144 h. However, when the substrate concentration was changed from 5% to 2% DM, the cellulose conversion increased to 79.7%. An increase from 5% to 10% DM resulted, however, in a similar degree of cellulose conversion, despite a significant increase in the glucose concentration from 23 g L-1 to 45 g L-1. The deactivation of beta -glucosidase increased with increasing residence time and was more pronounced with vigorous agitation. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biotechnology Progress
volume
17
issue
1
pages
110 - 117
publisher
The American Chemical Society
external identifiers
  • wos:000166824800011
  • scopus:0035125282
ISSN
1520-6033
DOI
10.1021/bp000145+
language
English
LU publication?
yes
id
774e5b4d-a685-4196-ab0a-bfac7f98f32f (old id 3911320)
date added to LUP
2013-07-01 08:27:40
date last changed
2018-02-18 04:32:25
@article{774e5b4d-a685-4196-ab0a-bfac7f98f32f,
  abstract     = {Softwood is an interesting raw material for the production of fuel ethanol as a result of its high content of hexoses, and it has attracted attention especially in the Northern hemisphere. However, the enzymatic hydrolysis of softwood is not sufficiently efficient for the complete conversion of cellulose to glucose. Since an improvement in the glucose yield is of great importance for the overall economy of the process, the influence of various parameters on the cellulose conversion of steam-pretreated spruce has been investigated. The addition of beta -glucosidase up to 50 IU g(-1) cellulose to the enzymatic hydrolysis process resulted in increased cellulose conversion at a cellulase loading up to 48 FPU g(-1) cellulose. Despite very high enzyme loading (120 FPU g(-1) cellulose) only about 50% of the cellulose in steam-pretreated spruce was converted to glucose when all of the material following pretreatment was used in the hydrolysis step. The influence of temperature, residence time, and pH were investigated for washed pretreated spruce at a dry matter (DM) content of 5% and a cellulase activity of 18.5 FPU g(-1) cellulose. The optimal temperature was found to be dependent on both residence time and pH, and the maximum degree of cellulose conversion, 69.2%, was obtained at 38 degreesC and pH 4.9 for a residence time of 144 h. However, when the substrate concentration was changed from 5% to 2% DM, the cellulose conversion increased to 79.7%. An increase from 5% to 10% DM resulted, however, in a similar degree of cellulose conversion, despite a significant increase in the glucose concentration from 23 g L-1 to 45 g L-1. The deactivation of beta -glucosidase increased with increasing residence time and was more pronounced with vigorous agitation.},
  author       = {Tengborg, C and Galbe, Mats and Zacchi, Guido},
  issn         = {1520-6033},
  language     = {eng},
  number       = {1},
  pages        = {110--117},
  publisher    = {The American Chemical Society},
  series       = {Biotechnology Progress},
  title        = {Influence of enzyme loading and physical parameters on the enzymatic hydrolysis of steam-pretreated softwood},
  url          = {http://dx.doi.org/10.1021/bp000145+},
  volume       = {17},
  year         = {2001},
}