Ethanolic fermentation of xylose with Saccharomyces cerevisiae harboring the Thermus thermophilus xylA gene, which expresses an active xylose (glucose) isomerase.

ABSTRACT In industrial fermentation processes, the yeast Saccharomyces cerevisiae is commonly used for ethanol production. However, it lacks the ability to ferment pentose sugars like d-xylose and l-arabinose. Heterologous expression of a xylose isomerase (XI) would enable yeast cells to metabolize xylose. However, many attempts to express a prokaryotic XI with high activity in S. cerevisiae have failed so far. We have screened nucleic acid databases for sequences encoding putative XIs and finally were able to clone and successfully express a highly active new kind of XI from the anaerobic bacterium Clostridium phytofermentans in S. cerevisiae. Heterologous expression of this enzyme confers on the yeast cells the ability to metabolize d-xylose and to use it as the sole carbon and energy source. The new enzyme has low sequence similarities to the XIs from Piromyces sp. strain E2 and Thermus thermophilus, which were the only two XIs previously functionally expressed in S. cerevisiae. The activity and kinetic parameters of the new enzyme are comparable to those of the Piromyces XI. Importantly, the new enzyme is far less inhibited by xylitol, which accrues as a side product during xylose fermentation. Furthermore, expression of the gene could be improved by adapting its codon usage to that of the highly expressed glycolytic genes of S. cerevisiae. Expression of the bacterial XI in an industrially employed yeast strain enabled it to grow on xylose and to ferment xylose to ethanol. Thus, our findings provide an excellent starting point for further improvement of xylose fermentation in industrial yeast strains.

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Heterologous expression of an esterase from Thermus thermophilus HB27 in Saccharomyces cerevisiae

Journal of Biotechnology ◽

10.1016/j.jbiotec.2009.11.017 ◽

2010 ◽

Vol 145 (3) ◽

pp. 226-232 ◽

Cited By ~ 19

Author(s):

Olalla López-López ◽

Pablo Fuciños ◽

Lorenzo Pastrana ◽

M. Luisa Rúa ◽

M. Esperanza Cerdán ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Heterologous Expression ◽

Thermus Thermophilus

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Adaptation to low pH and lignocellulosic inhibitors resulting in ethanolic fermentation and growth of Saccharomyces cerevisiae

AMB Express ◽

10.1186/s13568-016-0234-8 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 19

Author(s):

Venkatachalam Narayanan ◽

Violeta Sànchez i Nogué ◽

Ed W. J. van Niel ◽

Marie F. Gorwa-Grauslund

Keyword(s):

Saccharomyces Cerevisiae ◽

Low Ph ◽

Ethanolic Fermentation

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The influence of Cu concentration on ethanolic fermentation by Saccharomyces cerevisiae

Journal of Bioscience and Bioengineering ◽

10.1016/s1389-1723(00)80104-8 ◽

2000 ◽

Vol 90 (2) ◽

pp. 163-167 ◽

Cited By ~ 23

Author(s):

Manuel Azenha ◽

Maria Teresa Vasconcelos ◽

Pedro Moradas-Ferreira

Keyword(s):

Saccharomyces Cerevisiae ◽

Ethanolic Fermentation

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Fermentation of irradiated sugarcane must

Scientia Agricola ◽

10.1590/s0103-90162003000400011 ◽

2003 ◽

Vol 60 (4) ◽

pp. 677-681 ◽

Cited By ~ 4

Author(s):

André Ricardo Alcarde ◽

Júlio Marcos Melges Walder ◽

Jorge Horii

Keyword(s):

Saccharomyces Cerevisiae ◽

Gamma Radiation ◽

Dose Rate ◽

Ethanol Yield ◽

Ethanolic Fermentation ◽

Yeast Saccharomyces Cerevisiae ◽

Efficient Treatment ◽

Yeast Viability ◽

Volatile Acidity ◽

Lethal Doses

Bacillus and Lactobacillus are bacteria that usually contaminate the ethanolic fermentation by yeasts and may influence yeast viability. As microorganisms can be killed by ionizing radiation, the efficacy of gamma radiation in reducing the population of certain contaminating bacteria from sugarcane must was examined and, as a consequence, the beneficial effect of lethal doses of radiation on some parameters of yeast-based ethanolic fermentation was verified. Must from sugarcane juice was inoculated with bacteria of the genera Bacillus and Lactobacillus. The contaminated must was irradiated with 2.0, 4.0, 6.0, 8.0 and 10.0 kGy of gamma radiation. After ethanolic fermentation by the yeast (Saccharomyces cerevisiae) the total and volatile acidity produced during the process were evaluated; yeast viability and ethanol yield were also recorded. Treatments of gamma radiation reduced the population of the contaminating bacteria in the sugarcane must. The acidity produced during the fermentation decreased as the dose rate of radiation increased. Conversely, the yeast viability increased as the dose rate of radiation increased. Gamma irradiation was an efficient treatment to decontaminate the must and improved its parameters related to ethanolic fermentation, including ethanol yield, which increased 1.9%.

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