title: Sequential incubation of Candida shehatae and ethanol-tolerant yeast cells for efficient ethanol production from a mixture of glucose, xylose and cellobiose.
abstract: A mixture of 5% (w/v) glucose, 4% (w/v) xylose and 5% (w/v) cellobiose was fermented into ethanol using non-recombinant yeasts. Two series of experiments were carried out: (1) sequential fermentation with Candida shehatae D45-6 and Saccharomyces cerevisiae (Cs-Sc), and (2) sequential fermentation with C. shehatae D45-6 and Brettanomyces bruxellensis (Cs-Bb). C. shehatae D45-6 was initially used for glucose and xylose fermentation before adding highly ethanol-tolerant yeasts, either S. cerevisiae or B. bruxellensis, for cellobiose fermentation. For the sequential fermentation using S. cerevisiae, β-glucosidase was also included in the second step. In these two experiments, ethanol concentration reached 5.6-5.8% (w/v) and 99% sugar was consumed. Our results suggest that restricted glucose production from cellulose by saccharification could allow D45-6 to complete monosaccharide fermentation before the ethanol concentration exceeded its tolerance level.
authors.affiliation: National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan. kanteki9@affrc.go.jp
authors.forename: Di
authors.initials: D
authors.lastname: Guan
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Riki
authors.initials: R
authors.lastname: Shiroma
authors.forename: Masakazu
authors.initials: M
authors.lastname: Ike
authors.forename: Ken
authors.initials: K
authors.lastname: Tokuyasu
mesh_terms: D056804:Biofuels; D055168:Brettanomyces / Q000378:metabolism; D002175:Candida / Q000378:metabolism*; D002475:Cellobiose / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D000431:Ethanol; D005285:Fermentation; D005947:Glucose / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D014994:Xylose / Q000378:metabolism*; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D056804:Biofuels; D002475:Cellobiose; D000431:Ethanol; D014994:Xylose; D001617:beta-Glucosidase; D005947:Glucose