Ethanol production from xylo-oligosaccharides by xylose-fermenting Saccharomyces cerevisiae expressing β-xylosidase

Biosci Biotechnol Biochem. 2011;75(6):1140-6. doi: 10.1271/bbb.110043. Epub 2011 Jun 13.

Abstract

Construction of xylose- and xylo-oligosaccharide-fermenting Saccharomyces cerevisiae strains is important, because hydrolysates derived from lignocellulosic biomass contain significant amounts of these sugars. We have obtained recombinant S. cerevisiae strain MA-D4 (D-XKXDHXR), expressing xylose reductase, xylitol dehydrogenase and xylulokinase. In the present study, we generated recombinant strain D-XSD/XKXDHXR by transforming MA-D4 with a β-xylosidase gene cloned from the filamentous fungus Trichoderma reesei. The intracellular β-xylosidase-specific activity of D-XSD/XKXDHXR was high, while that of the control strain was under the limit of detection. D-XSD/XKXDHXR produced ethanol, and xylose accumulated in the culture supernatant under fermentation in a medium containing xylo-oligosaccharides as sole carbon source. β-Xylosidase-specific activity in D-XSD/XKXDHXR declined due to xylose both in vivo and in vitro. D-XSD/XKXDHXR converted xylo-oligosaccharides in an enzymatic hydrolysate of eucalyptus to ethanol. These results indicate that D-XSD/XKXDHXR efficiently converted xylo-oligosaccharides to xylose and subsequently to ethanol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehyde Reductase / genetics
  • Aldehyde Reductase / metabolism
  • Biofuels
  • D-Xylulose Reductase / genetics
  • D-Xylulose Reductase / metabolism
  • Ethanol / metabolism*
  • Fermentation
  • Industrial Microbiology / methods*
  • Lignin / metabolism*
  • Organisms, Genetically Modified / genetics
  • Organisms, Genetically Modified / growth & development
  • Organisms, Genetically Modified / metabolism
  • Phosphotransferases (Alcohol Group Acceptor) / genetics
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae / metabolism*
  • Trichoderma / chemistry
  • Trichoderma / genetics
  • Xylose / biosynthesis*
  • Xylosidases / genetics
  • Xylosidases / metabolism*

Substances

  • Biofuels
  • Ethanol
  • Lignin
  • Xylose
  • Aldehyde Reductase
  • D-Xylulose Reductase
  • Phosphotransferases (Alcohol Group Acceptor)
  • xylulokinase
  • Xylosidases
  • exo-1,4-beta-D-xylosidase