title: Ethanol production from xylo-oligosaccharides by xylose-fermenting Saccharomyces cerevisiae expressing β-xylosidase.
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.
authors.affiliation: Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Hiroshima, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Fujii
authors.forename: Guoce
authors.initials: G
authors.lastname: Yu
authors.forename: Akinori
authors.initials: A
authors.lastname: Matsushika
authors.forename: Asami
authors.initials: A
authors.lastname: Kurita
authors.forename: Shinichi
authors.initials: S
authors.lastname: Yano
authors.forename: Katsuji
authors.initials: K
authors.lastname: Murakami
authors.forename: Shigeki
authors.initials: S
authors.lastname: Sawayama
mesh_terms: D000449:Aldehyde Reductase / Q000235:genetics / Q000378:metabolism; D056804:Biofuels; D050542:D-Xylulose Reductase / Q000235:genetics / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D007218:Industrial Microbiology / Q000379:methods*; D008031:Lignin / Q000378:metabolism*; D030781:Organisms, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014242:Trichoderma / Q000737:chemistry / Q000235:genetics; D014994:Xylose / Q000096:biosynthesis*; D014995:Xylosidases / Q000235:genetics / Q000378:metabolism*
chemical_list: D056804:Biofuels; D000431:Ethanol; D008031:Lignin; D014994:Xylose; D000449:Aldehyde Reductase; D050542:D-Xylulose Reductase; D017853:Phosphotransferases (Alcohol Group Acceptor); C032700:xylulokinase; D014995:Xylosidases; C026579:exo-1,4-beta-D-xylosidase