Fermentation to ethanol of pentose-containing spent sulfite liquor
Ethanolic fermentation of spent sulfite liquor with ordinary bakers' yeast is incomplete because of this yeast cannot ferment the pentose sugars in the liquor. This results in poor alcohol yields, and a residual effluent problem. By using the yeast Candida shehatae (R) for fermentation of the spent sulfite liquor from a large Canadian alcohol-producing sulfite pulp and paper mill, pentoses as well as hexoses were fermented nearly completely, alcohol yields were raised by 33%, and sugar removal increased by 46%. Inhibitors were removed prior to fermentation by steam stripping. Major benefits were obtained by careful recycling of this yeast, which was shown to be tolerant both of high sugar concentrations and high alcohol concentrations. When sugar concentrations over 250 g/L (glucose:xylose 70:30) were fermented, ethanol became an inhibitor when its concentration reached over 90 g/L. However, when the ethanol was removed by low-temperature vacuum distillation, fermentation continued and resulted in a yield of 0.50 g ethanol/g sugar consumed. Further improvement was achieved by combining enzyme saccharification of sugar oligomers with fermentation. This yeast is able to ferment both hexoses and pentoses simultaneously, efficiently, and rapidly.
- Research Organization:
- Univ. of Toronto, Ontario
- OSTI ID:
- 6433657
- Journal Information:
- Biotechnol. Bioeng.; (United States), Journal Name: Biotechnol. Bioeng.; (United States) Vol. 29:9; ISSN BIBIA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
090222* -- Alcohol Fuels-- Preparation from Wastes or Biomass-- (1976-1989)
ALCOHOLS
BIOCONVERSION
CANDIDA
CARBOHYDRATES
CHEMICAL REACTIONS
DECOMPOSITION
EFFICIENCY
ETHANOL
FERMENTATION
FUNGI
HEXOSES
HYDROLYSIS
HYDROXY COMPOUNDS
LYSIS
MICROORGANISMS
MONOSACCHARIDES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PENTOSES
PLANTS
SACCHARIDES
SACCHARIFICATION
SOLVOLYSIS
SULFITES
SULFUR COMPOUNDS
YEASTS
YIELDS