title: Efficient conversion of xylose to ethanol by stress-tolerant Kluyveromyces marxianus BUNL-21.
abstract: The fermentation ability of thermotolerant Kluyveromyces marxianus BUNL-21 isolated in Laos was investigated. Comparison with thermotolerant K. marxianus DMKU3-1042 as one of the most thermotolerant yeasts isolated previously revealed that the strain possesses stronger ability for conversion of xylose to ethanol, resistance to 2-deoxyglucose in the case of pentose, and tolerance to various stresses including high temperature and hydrogen peroxide. K. marxianus BUNL-21 was found to have ethanol fermentation activity from xylose that is slightly lower and much higher than that of Scheffersomyces stipitis (Pichia stipitis) at 30 °C and at higher temperatures, respectively. The lower ethanol production seems to be due to large accumulation of acetic acid. The possible mechanism of acetic acid accumulation is discussed. In addition, it was found that both K. marxianus strains produced ethanol in the presence of 10 mM hydroxymethylfurfural or furfural, at a level almost equivalent to that in their absence. Therefore, K. marxianus BUNL-21 is a highly competent yeast for high-temperature ethanol fermentation with lignocellulosic biomass.
authors.affiliation: Applied Molecular Bioscience, Graduate School of Medicine, Yamaguchi University, Ube, 755-8505 Japan.
authors.forename: Sukanya
authors.initials: S
authors.lastname: Nitiyon
authors.affiliation: Department of Biology, Faculty of Science, National University of Laos, Vientiane, Lao PDR.
authors.forename: Chansom
authors.initials: C
authors.lastname: Keo-Oudone
authors.affiliation: Applied Molecular Bioscience, Graduate School of Medicine, Yamaguchi University, Ube, 755-8505 Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Murata
authors.affiliation: Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok, 10900 Thailand.
authors.forename: Noppon
authors.initials: N
authors.lastname: Lertwattanasakul
authors.affiliation: Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok, 10900 Thailand.
authors.forename: Savitree
authors.initials: S
authors.lastname: Limtong
authors.affiliation: Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, 753-8515 Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kosaka
authors.affiliation: Applied Molecular Bioscience, Graduate School of Medicine, Yamaguchi University, Ube, 755-8505 Japan ; Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, 753-8515 Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Yamada
keywords: Ethanol fermentation on xylose; Kluyveromyces marxianus; Stress resistance; Thermotolerant yeast