Expression of Vitreoscilla hemoglobin improves the metabolism of xylose in recombinant yeast Saccharomyces cerevisiae under low oxygen conditions

Laura Ruohonen, Aristos Aristidou, Alexander D. Frey, Merja Penttilä, Pauli T. Kallio

Research output: Contribution to journalArticleScientificpeer-review

29 Citations (Scopus)

Abstract

The yeast Saccharomyces cerevisiae efficiently ferments hexose sugars to ethanol, but it is unable to utilize xylose, a pentose sugar abundant in lignocellulosic materials. Recombinant yeast strains capable of xylose metabolism have been reported, however, such strains ferment xylose to ethanol poorly, with significantly lower yields and/or production rates compared to glucose. Our previous studies have indicated that oxygen is one of the key parameters in improving xylose consumption and ethanol yields. In addition, it has been shown that expression of the Vitreoscilla hemoglobin gene (vhb) in Escherichia coli leads to a more oxidized state of the cells under low oxygen concentrations. Therefore, we wanted to investigate the possible benefits expression of VHb encoding gene could bring to xylose fermentation in the recombinant S. cerevisiae yeast strain. Our results indicate that under low hypoxic fermentation conditions VHb improves the ethanol yield from the xylose metabolized. Less carbon was lost in xylitol, which is the major unwanted side product of the xylose-to-ethanol fermentation process.

Original languageEnglish
Pages (from-to)6-14
JournalEnzyme and Microbial Technology
Volume39
Issue number1
DOIs
Publication statusPublished - 1 Jun 2006
MoE publication typeA1 Journal article-refereed

Keywords

  • Ethanol
  • Saccharomyces cerevisiae
  • Vitreoscilla hemoglobin (VHb)
  • Xylose

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