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The generation of fermentation inhibitors during dilute acid hydrolysis of softwood

Larsson, S; Palmqvist, E; Hahn-Hägerdal, Bärbel LU ; Tengborg, C; Stenberg, K; Zacchi, Guido LU and Nilvebrant, NO (1999) In Enzyme and Microbial Technology 24(3-4). p.151-159
Abstract
The influence of the severity of dilute sulfuric acid hydrolysis of spruce (softwood) on sugar yield and on the fermentability of the hydrolysate by Saccharomyces cerevisiae (Baker's yeast) was investigated. Fermentability was assessed as the ethanol yield on fermentable sugars (mannose and glucose) and the mean volumetric productivity (4 h). The hydrolysis conditions, residence time, temperature, and sulfuric acid concentration were treated as a single parameter, combined severity (CS). When the CS of the hydrolysis conditions increased, the yield of fermentable sugars increased to a maximum between CS 2.0-2.7 for mannose, and 3.0-3.4 for glucose above which it decreased. The decrease in the yield of monosaccharides coincided with the... (More)
The influence of the severity of dilute sulfuric acid hydrolysis of spruce (softwood) on sugar yield and on the fermentability of the hydrolysate by Saccharomyces cerevisiae (Baker's yeast) was investigated. Fermentability was assessed as the ethanol yield on fermentable sugars (mannose and glucose) and the mean volumetric productivity (4 h). The hydrolysis conditions, residence time, temperature, and sulfuric acid concentration were treated as a single parameter, combined severity (CS). When the CS of the hydrolysis conditions increased, the yield of fermentable sugars increased to a maximum between CS 2.0-2.7 for mannose, and 3.0-3.4 for glucose above which it decreased. The decrease in the yield of monosaccharides coincided with the maximum concentrations of furfural and 5-hydroxymethylfurfural (5HMF). With the further increase in CS, the concentrations of furfural and 5-HMF decreased while the formation of formic acid and levulinic acid increased The yield of ethanol decreased at approximately CS 3; however, the volumetric productivity decreased at lower CS. The effect of acetic acid, formic acid, levulinic acid furfural, and 5-HMF on fermentability was assayed in model fermentations Ethanol yield and volumetric productivity decreased with increasing concentrations of acetic acid, formic acid, and levulinic acid. Furfural and 5-HMF decreased the volumetric productivity but did not influence the final yield of ethanol. The decrease in volumetric productivity was more pronounced when 5-HMF was added to the fermentation, and this compound was depleted at a lower rate than furfural. The inhibition observed in hydrolysates produced in higher CS could not be fully explained by the effect of the by-products furfural, 5-HMF, acetic acid, formic acid: and levulinic acid. (C) 1998 Elsevier Science Inc. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
dilute acid hydrolysis, ethanolic fermentation, fermentation inhibitors, weak acids, Saccharomyces cerevisiae
in
Enzyme and Microbial Technology
volume
24
issue
3-4
pages
151 - 159
publisher
Elsevier
external identifiers
  • wos:000077716000005
  • scopus:0345722732
ISSN
0141-0229
DOI
10.1016/S0141-0229(98)00101-X
language
English
LU publication?
yes
id
e61527c3-1d0d-4457-9757-1c9aed71f9b4 (old id 3911415)
date added to LUP
2013-06-28 14:28:42
date last changed
2017-11-19 03:26:02
@article{e61527c3-1d0d-4457-9757-1c9aed71f9b4,
  abstract     = {The influence of the severity of dilute sulfuric acid hydrolysis of spruce (softwood) on sugar yield and on the fermentability of the hydrolysate by Saccharomyces cerevisiae (Baker's yeast) was investigated. Fermentability was assessed as the ethanol yield on fermentable sugars (mannose and glucose) and the mean volumetric productivity (4 h). The hydrolysis conditions, residence time, temperature, and sulfuric acid concentration were treated as a single parameter, combined severity (CS). When the CS of the hydrolysis conditions increased, the yield of fermentable sugars increased to a maximum between CS 2.0-2.7 for mannose, and 3.0-3.4 for glucose above which it decreased. The decrease in the yield of monosaccharides coincided with the maximum concentrations of furfural and 5-hydroxymethylfurfural (5HMF). With the further increase in CS, the concentrations of furfural and 5-HMF decreased while the formation of formic acid and levulinic acid increased The yield of ethanol decreased at approximately CS 3; however, the volumetric productivity decreased at lower CS. The effect of acetic acid, formic acid, levulinic acid furfural, and 5-HMF on fermentability was assayed in model fermentations Ethanol yield and volumetric productivity decreased with increasing concentrations of acetic acid, formic acid, and levulinic acid. Furfural and 5-HMF decreased the volumetric productivity but did not influence the final yield of ethanol. The decrease in volumetric productivity was more pronounced when 5-HMF was added to the fermentation, and this compound was depleted at a lower rate than furfural. The inhibition observed in hydrolysates produced in higher CS could not be fully explained by the effect of the by-products furfural, 5-HMF, acetic acid, formic acid: and levulinic acid. (C) 1998 Elsevier Science Inc.},
  author       = {Larsson, S and Palmqvist, E and Hahn-Hägerdal, Bärbel and Tengborg, C and Stenberg, K and Zacchi, Guido and Nilvebrant, NO},
  issn         = {0141-0229},
  keyword      = {dilute acid hydrolysis,ethanolic fermentation,fermentation inhibitors,weak acids,Saccharomyces cerevisiae},
  language     = {eng},
  number       = {3-4},
  pages        = {151--159},
  publisher    = {Elsevier},
  series       = {Enzyme and Microbial Technology},
  title        = {The generation of fermentation inhibitors during dilute acid hydrolysis of softwood},
  url          = {http://dx.doi.org/10.1016/S0141-0229(98)00101-X},
  volume       = {24},
  year         = {1999},
}