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Process design of SSCF for ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw

Bondesson, Pia-Maria LU and Galbe, Mats LU (2016) In Biotechnology for Biofuels 9(1).
Abstract
Background
Pretreatment is an important step in the production of ethanol from lignocellulosic material. Using acetic acid together with steam pretreatment allows the positive effects of an acid catalyst to be retained, while avoiding the negative environmental effects associated with sulphuric acid. Acetic acid is also formed during the pretreatment and hydrolysis of hemicellulose, and is a known inhibitor that may impair fermentation at high concentrations. The purpose of this study was to improve ethanol production from glucose and xylose in steam-pretreated, acetic-acid-impregnated wheat straw by process design of simultaneous saccharification and co-fermentation (SSCF), using a genetically modified pentose fermenting yeast strain... (More)
Background
Pretreatment is an important step in the production of ethanol from lignocellulosic material. Using acetic acid together with steam pretreatment allows the positive effects of an acid catalyst to be retained, while avoiding the negative environmental effects associated with sulphuric acid. Acetic acid is also formed during the pretreatment and hydrolysis of hemicellulose, and is a known inhibitor that may impair fermentation at high concentrations. The purpose of this study was to improve ethanol production from glucose and xylose in steam-pretreated, acetic-acid-impregnated wheat straw by process design of simultaneous saccharification and co-fermentation (SSCF), using a genetically modified pentose fermenting yeast strain Saccharomyces cerevisiae.

Results
Ethanol was produced from glucose and xylose using both the liquid fraction and the whole slurry from pretreated materials. The highest ethanol concentration achieved was 37.5 g/L, corresponding to an overall ethanol yield of 0.32 g/g based on the glucose and xylose available in the pretreated material. To obtain this concentration, a slurry with a water-insoluble solids (WIS) content of 11.7 % was used, using a fed-batch SSCF strategy. A higher overall ethanol yield (0.36 g/g) was obtained at 10 % WIS.

Conclusions
Ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw through SSCF with a pentose fermenting S. cerevisiae strain was successfully demonstrated. However, the ethanol concentration was too low and the residence time too long to be suitable for large-scale applications. It is hoped that further process design focusing on the enzymatic conversion of cellulose to glucose will allow the combination of acetic acid pretreatment and co-fermentation of glucose and xylose. (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
Acetic acid , Wheat straw , Steam pretreatment , Ethanol , Simultaneous saccharification and co-fermentation (SSCF) , Fed-batch , Saccharomyces cerevisiae
in
Biotechnology for Biofuels
volume
9
issue
1
publisher
BioMed Central
external identifiers
  • wos:000385581100007
  • scopus:84992195184
ISSN
1754-6834
DOI
10.1186/s13068-016-0635-6
language
English
LU publication?
yes
id
ab581975-f63d-492d-a63e-cf895452d5fc
date added to LUP
2016-10-19 09:29:16
date last changed
2017-08-27 06:26:19
@article{ab581975-f63d-492d-a63e-cf895452d5fc,
  abstract     = {Background<br/>Pretreatment is an important step in the production of ethanol from lignocellulosic material. Using acetic acid together with steam pretreatment allows the positive effects of an acid catalyst to be retained, while avoiding the negative environmental effects associated with sulphuric acid. Acetic acid is also formed during the pretreatment and hydrolysis of hemicellulose, and is a known inhibitor that may impair fermentation at high concentrations. The purpose of this study was to improve ethanol production from glucose and xylose in steam-pretreated, acetic-acid-impregnated wheat straw by process design of simultaneous saccharification and co-fermentation (SSCF), using a genetically modified pentose fermenting yeast strain Saccharomyces cerevisiae.<br/><br/>Results<br/>Ethanol was produced from glucose and xylose using both the liquid fraction and the whole slurry from pretreated materials. The highest ethanol concentration achieved was 37.5 g/L, corresponding to an overall ethanol yield of 0.32 g/g based on the glucose and xylose available in the pretreated material. To obtain this concentration, a slurry with a water-insoluble solids (WIS) content of 11.7 % was used, using a fed-batch SSCF strategy. A higher overall ethanol yield (0.36 g/g) was obtained at 10 % WIS.<br/><br/>Conclusions<br/>Ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw through SSCF with a pentose fermenting S. cerevisiae strain was successfully demonstrated. However, the ethanol concentration was too low and the residence time too long to be suitable for large-scale applications. It is hoped that further process design focusing on the enzymatic conversion of cellulose to glucose will allow the combination of acetic acid pretreatment and co-fermentation of glucose and xylose.},
  articleno    = {222},
  author       = {Bondesson, Pia-Maria and Galbe, Mats},
  issn         = {1754-6834},
  keyword      = {Acetic acid ,Wheat straw ,Steam pretreatment ,Ethanol ,Simultaneous saccharification and co-fermentation (SSCF) ,Fed-batch ,Saccharomyces cerevisiae },
  language     = {eng},
  month        = {10},
  number       = {1},
  publisher    = {BioMed Central},
  series       = {Biotechnology for Biofuels},
  title        = {Process design of SSCF for ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw},
  url          = {http://dx.doi.org/10.1186/s13068-016-0635-6},
  volume       = {9},
  year         = {2016},
}