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Comparing the xylose reductase/xylitol dehydrogenase and xylose isomerase pathways in arabinose and xylose fermenting Saccharomyces cerevisiae strains

Bettiga, Maurizio LU ; Hahn-Hägerdal, Bärbel LU and Gorwa-Grauslund, Marie-Francoise LU (2008) In Biotechnology for Biofuels 1.
Abstract
Background: Ethanolic fermentation of lignocellulosic biomass is a sustainable option for the production

of bioethanol. This process would greatly benefit from recombinant Saccharomyces cerevisiae strains also

able to ferment, besides the hexose sugar fraction, the pentose sugars, arabinose and xylose. Different

pathways can be introduced in S. cerevisiae to provide arabinose and xylose utilisation. In this study, the

bacterial arabinose isomerase pathway was combined with two different xylose utilisation pathways: the

xylose reductase/xylitol dehydrogenase and xylose isomerase pathways, respectively, in genetically

identical strains. The strains were compared with respect to aerobic... (More)
Background: Ethanolic fermentation of lignocellulosic biomass is a sustainable option for the production

of bioethanol. This process would greatly benefit from recombinant Saccharomyces cerevisiae strains also

able to ferment, besides the hexose sugar fraction, the pentose sugars, arabinose and xylose. Different

pathways can be introduced in S. cerevisiae to provide arabinose and xylose utilisation. In this study, the

bacterial arabinose isomerase pathway was combined with two different xylose utilisation pathways: the

xylose reductase/xylitol dehydrogenase and xylose isomerase pathways, respectively, in genetically

identical strains. The strains were compared with respect to aerobic growth in arabinose and xylose batch

culture and in anaerobic batch fermentation of a mixture of glucose, arabinose and xylose.

Results: The specific aerobic arabinose growth rate was identical, 0.03 h-1, for the xylose reductase/xylitol

dehydrogenase and xylose isomerase strain. The xylose reductase/xylitol dehydrogenase strain displayed

higher aerobic growth rate on xylose, 0.14 h-1, and higher specific xylose consumption rate in anaerobic

batch fermentation, 0.09 g (g cells)-1 h-1 than the xylose isomerase strain, which only reached 0.03 h-1 and

0.02 g (g cells)-1h-1, respectively. Whereas the xylose reductase/xylitol dehydrogenase strain produced

higher ethanol yield on total sugars, 0.23 g g-1 compared with 0.18 g g-1 for the xylose isomerase strain, the

xylose isomerase strain achieved higher ethanol yield on consumed sugars, 0.41 g g-1 compared with 0.32

g g-1 for the xylose reductase/xylitol dehydrogenase strain. Anaerobic fermentation of a mixture of glucose,

arabinose and xylose resulted in higher final ethanol concentration, 14.7 g l-1 for the xylose reductase/

xylitol dehydrogenase strain compared with 11.8 g l-1 for the xylose isomerase strain, and in higher specific

ethanol productivity, 0.024 g (g cells)-1 h-1 compared with 0.01 g (g cells)-1 h-1 for the xylose reductase/

xylitol dehydrogenase strain and the xylose isomerase strain, respectively.

Conclusion: The combination of the xylose reductase/xylitol dehydrogenase pathway and the bacterial

arabinose isomerase pathway resulted in both higher pentose sugar uptake and higher overall ethanol

production than the combination of the xylose isomerase pathway and the bacterial arabinose isomerase

pathway. Moreover, the flux through the bacterial arabinose pathway did not increase when combined

with the xylose isomerase pathway. This suggests that the low activity of the bacterial arabinose pathway

cannot be ascribed to arabitol formation via the xylose reductase enzyme. (Less)
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Contribution to journal
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published
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Biotechnology for Biofuels
volume
1
publisher
BioMed Central
external identifiers
  • WOS:000272005600001
  • Scopus:56449084752
ISSN
1754-6834
DOI
10.1186/1754-6834-1-16
language
English
LU publication?
yes
id
2402c802-638e-4354-8eca-14be920630b3 (old id 1488371)
date added to LUP
2009-10-26 11:33:14
date last changed
2016-10-13 04:45:24
@misc{2402c802-638e-4354-8eca-14be920630b3,
  abstract     = {Background: Ethanolic fermentation of lignocellulosic biomass is a sustainable option for the production<br/><br>
of bioethanol. This process would greatly benefit from recombinant Saccharomyces cerevisiae strains also<br/><br>
able to ferment, besides the hexose sugar fraction, the pentose sugars, arabinose and xylose. Different<br/><br>
pathways can be introduced in S. cerevisiae to provide arabinose and xylose utilisation. In this study, the<br/><br>
bacterial arabinose isomerase pathway was combined with two different xylose utilisation pathways: the<br/><br>
xylose reductase/xylitol dehydrogenase and xylose isomerase pathways, respectively, in genetically<br/><br>
identical strains. The strains were compared with respect to aerobic growth in arabinose and xylose batch<br/><br>
culture and in anaerobic batch fermentation of a mixture of glucose, arabinose and xylose.<br/><br>
Results: The specific aerobic arabinose growth rate was identical, 0.03 h-1, for the xylose reductase/xylitol<br/><br>
dehydrogenase and xylose isomerase strain. The xylose reductase/xylitol dehydrogenase strain displayed<br/><br>
higher aerobic growth rate on xylose, 0.14 h-1, and higher specific xylose consumption rate in anaerobic<br/><br>
batch fermentation, 0.09 g (g cells)-1 h-1 than the xylose isomerase strain, which only reached 0.03 h-1 and<br/><br>
0.02 g (g cells)-1h-1, respectively. Whereas the xylose reductase/xylitol dehydrogenase strain produced<br/><br>
higher ethanol yield on total sugars, 0.23 g g-1 compared with 0.18 g g-1 for the xylose isomerase strain, the<br/><br>
xylose isomerase strain achieved higher ethanol yield on consumed sugars, 0.41 g g-1 compared with 0.32<br/><br>
g g-1 for the xylose reductase/xylitol dehydrogenase strain. Anaerobic fermentation of a mixture of glucose,<br/><br>
arabinose and xylose resulted in higher final ethanol concentration, 14.7 g l-1 for the xylose reductase/<br/><br>
xylitol dehydrogenase strain compared with 11.8 g l-1 for the xylose isomerase strain, and in higher specific<br/><br>
ethanol productivity, 0.024 g (g cells)-1 h-1 compared with 0.01 g (g cells)-1 h-1 for the xylose reductase/<br/><br>
xylitol dehydrogenase strain and the xylose isomerase strain, respectively.<br/><br>
Conclusion: The combination of the xylose reductase/xylitol dehydrogenase pathway and the bacterial<br/><br>
arabinose isomerase pathway resulted in both higher pentose sugar uptake and higher overall ethanol<br/><br>
production than the combination of the xylose isomerase pathway and the bacterial arabinose isomerase<br/><br>
pathway. Moreover, the flux through the bacterial arabinose pathway did not increase when combined<br/><br>
with the xylose isomerase pathway. This suggests that the low activity of the bacterial arabinose pathway<br/><br>
cannot be ascribed to arabitol formation via the xylose reductase enzyme.},
  author       = {Bettiga, Maurizio and Hahn-Hägerdal, Bärbel and Gorwa-Grauslund, Marie-Francoise},
  issn         = {1754-6834},
  language     = {eng},
  publisher    = {ARRAY(0x9b52ad8)},
  series       = {Biotechnology for Biofuels},
  title        = {Comparing the xylose reductase/xylitol dehydrogenase and xylose isomerase pathways in arabinose and xylose fermenting Saccharomyces cerevisiae strains},
  url          = {http://dx.doi.org/10.1186/1754-6834-1-16},
  volume       = {1},
  year         = {2008},
}