Advanced

Combining the effects of process design and pH for improved xylose conversion in high solid ethanol production from Arundo donax.

Palmqvist, Benny LU and Lidén, Gunnar LU (2014) In AMB Express 4.
Abstract
The impact of pH coupled to process design for the conversion of the energy crop Arundo donax to ethanol was assessed in the present study under industrially relevant solids loadings. Two main process strategies were investigated, i.e. the traditional simultaneous saccharification and co-fermentation (SSCF) and a HYBRID design, where a long high temperature enzymatic hydrolysis step was carried out prior to continued low temperature SSCF, keeping the same total reaction time. Since acetic acid was identified as the major inhibitor in the slurry, the scenarios were investigated under different fermentation pH in order to alleviate the inhibitory effect on, in particular, xylose conversion. The results show that, regardless of fermentation... (More)
The impact of pH coupled to process design for the conversion of the energy crop Arundo donax to ethanol was assessed in the present study under industrially relevant solids loadings. Two main process strategies were investigated, i.e. the traditional simultaneous saccharification and co-fermentation (SSCF) and a HYBRID design, where a long high temperature enzymatic hydrolysis step was carried out prior to continued low temperature SSCF, keeping the same total reaction time. Since acetic acid was identified as the major inhibitor in the slurry, the scenarios were investigated under different fermentation pH in order to alleviate the inhibitory effect on, in particular, xylose conversion. The results show that, regardless of fermentation pH, a higher glucan conversion could be achieved with the HYBRID approach compared to SSCF. Furthermore, it was found that increasing the pH from 5.0 to 5.5 for the fermentation phase had a large positive effect on xylose consumption for both process designs, although the SSCF design was more favored. With the high sugar concentrations available at the start of fermentation during the HYBRID design, the ethanol yield was reduced in favor of cell growth and glycerol production. This finding was confirmed in shake flask fermentations where an increase in pH enhanced both glucose and xylose consumption, but also cell growth and cell yield with the overall effect being a reduced ethanol yield. In conclusion this resulted in similar overall ethanol yields at the different pH values for the HYBRID design, despite the improved xylose uptake, whereas a significant increase in overall ethanol yield was found with the SSCF design. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
AMB Express
volume
4
publisher
Springer Open
external identifiers
  • pmid:24949274
  • scopus:84934764527
ISSN
2191-0855
DOI
10.1186/s13568-014-0041-z
language
English
LU publication?
yes
id
093e7a24-69ab-4514-9b35-4ad9bc491ce4 (old id 4527853)
date added to LUP
2014-07-25 09:50:44
date last changed
2017-09-10 04:21:25
@article{093e7a24-69ab-4514-9b35-4ad9bc491ce4,
  abstract     = {The impact of pH coupled to process design for the conversion of the energy crop Arundo donax to ethanol was assessed in the present study under industrially relevant solids loadings. Two main process strategies were investigated, i.e. the traditional simultaneous saccharification and co-fermentation (SSCF) and a HYBRID design, where a long high temperature enzymatic hydrolysis step was carried out prior to continued low temperature SSCF, keeping the same total reaction time. Since acetic acid was identified as the major inhibitor in the slurry, the scenarios were investigated under different fermentation pH in order to alleviate the inhibitory effect on, in particular, xylose conversion. The results show that, regardless of fermentation pH, a higher glucan conversion could be achieved with the HYBRID approach compared to SSCF. Furthermore, it was found that increasing the pH from 5.0 to 5.5 for the fermentation phase had a large positive effect on xylose consumption for both process designs, although the SSCF design was more favored. With the high sugar concentrations available at the start of fermentation during the HYBRID design, the ethanol yield was reduced in favor of cell growth and glycerol production. This finding was confirmed in shake flask fermentations where an increase in pH enhanced both glucose and xylose consumption, but also cell growth and cell yield with the overall effect being a reduced ethanol yield. In conclusion this resulted in similar overall ethanol yields at the different pH values for the HYBRID design, despite the improved xylose uptake, whereas a significant increase in overall ethanol yield was found with the SSCF design.},
  articleno    = {41},
  author       = {Palmqvist, Benny and Lidén, Gunnar},
  issn         = {2191-0855},
  language     = {eng},
  publisher    = {Springer Open},
  series       = {AMB Express},
  title        = {Combining the effects of process design and pH for improved xylose conversion in high solid ethanol production from Arundo donax.},
  url          = {http://dx.doi.org/10.1186/s13568-014-0041-z},
  volume       = {4},
  year         = {2014},
}