Sequential Targeting of Xylose and Glucose Conversion in Fed-Batch Simultaneous Saccharification and Co-fermentation of Steam-Pretreated Wheat Straw for Improved Xylose Conversion to Ethanol
Nielsen, Fredrik LU ; Zacchi, Guido LU ; Galbe, Mats LU and Wallberg, Ola LU
(2017)
In Bioenergy Research
10(3).
p.800-810
- Abstract
Efficient conversion of both glucose and xylose in lignocellulosic biomass is necessary to make second-generation bioethanol from agricultural residues competitive with first-generation bioethanol and gasoline. Simultaneous saccharification and co-fermentation (SSCF) is a promising strategy for obtaining high ethanol yields. However, with this method, the xylose-fermenting capacity and viability of yeast tend to decline over time and restrict the xylose utilization. In this study, we examined the ethanol production from steam-pretreated wheat straw using an established SSCF strategy with substrate and enzyme feeding that was previously applied to steam-pretreated corn cobs. Based on our findings, we propose an alternative SSCF strategy... (More)
Efficient conversion of both glucose and xylose in lignocellulosic biomass is necessary to make second-generation bioethanol from agricultural residues competitive with first-generation bioethanol and gasoline. Simultaneous saccharification and co-fermentation (SSCF) is a promising strategy for obtaining high ethanol yields. However, with this method, the xylose-fermenting capacity and viability of yeast tend to decline over time and restrict the xylose utilization. In this study, we examined the ethanol production from steam-pretreated wheat straw using an established SSCF strategy with substrate and enzyme feeding that was previously applied to steam-pretreated corn cobs. Based on our findings, we propose an alternative SSCF strategy to sustain the xylose-fermenting capacity and improve the ethanol yield. The xylose-rich hydrolyzate liquor was separated from the glucose-rich solids, and phases were co-fermented sequentially. By prefermentation of the hydrolyzate liquor followed fed-batch SSCF, xylose, and glucose conversion could be targeted in succession. Because the xylose-fermenting capacity declines over time, while glucose is still converted, it was advantageous to target xylose conversion upfront. With our strategy, an overall ethanol yield of 84% of the theoretical maximum based on both xylose and glucose was reached for a slurry with higher inhibitor concentrations, versus 92% for a slurry with lower inhibitor concentrations. Xylose utilization exceeded 90% after SSCF for both slurries. Sequential targeting of xylose and glucose conversion sustained xylose fermentation and improved xylose utilization and ethanol yield compared with fed-batch SSCF of whole slurry.
(Less)
- author
- Nielsen, Fredrik
LU
; Zacchi, Guido
LU
; Galbe, Mats
LU
and Wallberg, Ola
LU
- organization
- publishing date
- 2017-09
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Co-fermentation, Ethanol, Lignocellulose, Prefermentation, Saccharomyces cerevisiae, Xylose
- in
- Bioenergy Research
- volume
- 10
- issue
- 3
- pages
- 800 - 810
- publisher
- Springer
- external identifiers
-
- wos:000406743700018
- scopus:85018690885
- ISSN
- 1939-1234
- DOI
- 10.1007/s12155-017-9841-8
- language
- English
- LU publication?
- yes
- id
- 1ba1f79b-a9bd-40d8-ad82-ed34056207a2
- date added to LUP
- 2017-05-23 14:59:44
- date last changed
- 2024-01-13 21:28:26
@article{1ba1f79b-a9bd-40d8-ad82-ed34056207a2,
abstract = {{<p>Efficient conversion of both glucose and xylose in lignocellulosic biomass is necessary to make second-generation bioethanol from agricultural residues competitive with first-generation bioethanol and gasoline. Simultaneous saccharification and co-fermentation (SSCF) is a promising strategy for obtaining high ethanol yields. However, with this method, the xylose-fermenting capacity and viability of yeast tend to decline over time and restrict the xylose utilization. In this study, we examined the ethanol production from steam-pretreated wheat straw using an established SSCF strategy with substrate and enzyme feeding that was previously applied to steam-pretreated corn cobs. Based on our findings, we propose an alternative SSCF strategy to sustain the xylose-fermenting capacity and improve the ethanol yield. The xylose-rich hydrolyzate liquor was separated from the glucose-rich solids, and phases were co-fermented sequentially. By prefermentation of the hydrolyzate liquor followed fed-batch SSCF, xylose, and glucose conversion could be targeted in succession. Because the xylose-fermenting capacity declines over time, while glucose is still converted, it was advantageous to target xylose conversion upfront. With our strategy, an overall ethanol yield of 84% of the theoretical maximum based on both xylose and glucose was reached for a slurry with higher inhibitor concentrations, versus 92% for a slurry with lower inhibitor concentrations. Xylose utilization exceeded 90% after SSCF for both slurries. Sequential targeting of xylose and glucose conversion sustained xylose fermentation and improved xylose utilization and ethanol yield compared with fed-batch SSCF of whole slurry.</p>}},
author = {{Nielsen, Fredrik and Zacchi, Guido and Galbe, Mats and Wallberg, Ola}},
issn = {{1939-1234}},
keywords = {{Co-fermentation; Ethanol; Lignocellulose; Prefermentation; Saccharomyces cerevisiae; Xylose}},
language = {{eng}},
number = {{3}},
pages = {{800--810}},
publisher = {{Springer}},
series = {{Bioenergy Research}},
title = {{Sequential Targeting of Xylose and Glucose Conversion in Fed-Batch Simultaneous Saccharification and Co-fermentation of Steam-Pretreated Wheat Straw for Improved Xylose Conversion to Ethanol}},
url = {{http://dx.doi.org/10.1007/s12155-017-9841-8}},
doi = {{10.1007/s12155-017-9841-8}},
volume = {{10}},
year = {{2017}},
}