Fermentation to ethanol of pentose-containing spent sulphite liquor

Journal Article · Mon Jun 01 04:00:00 EDT 1987 · Biotechnol. Bioeng.; (United States)

DOI:https://doi.org/10.1002/bit.260290915· OSTI ID:5595542

Yu, S; Wayman, M; Parekh, S K

Ethanolic fermentation of spent sulphite liquor with ordinary bakers' yeast is incomplete because 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 sulphite liquor from a large Canadian alcohol-producing sulphite 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 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. Present indications are that it is well suited to industrial operations wherever hexoses and pentoses are both to be fermented to ethanol, for example, in wood hydrolysates. (Refs. 6).

• Research Organization: Univ. Toronto, Toronto, Ontario, M5S 1A4. Dept. of Chemical Engineering and Applied Chemistry
• OSTI ID: 5595542
• Journal Information: Biotechnol. Bioeng.; (United States), Journal Name: Biotechnol. Bioeng.; (United States) Vol. 29; ISSN BIBIA
• Country of Publication: United States
• Language: English

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54 ENVIRONMENTAL SCIENCES
ALCOHOLS
BAKING
BIOCONVERSION
CANDIDA
CARBOHYDRATES
CHEMICAL REACTIONS
DECOMPOSITION
DISTILLATION
ENZYMES
ETHANOL
EVAPORATION
FERMENTATION
FLASHING
FUNGI
HEATING
HEXOSES
HYDROGEN COMPOUNDS
HYDROLYSIS
HYDROXY COMPOUNDS
INDUSTRY
INHIBITION
LIQUID WASTES
LYSIS
MICROORGANISMS
MONOSACCHARIDES
OPERATION
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PAPER INDUSTRY
PENTOSES
PHASE TRANSFORMATIONS
PLANTS
QUANTITY RATIO
RECYCLING
REMOVAL
SACCHARIDES
SACCHARIFICATION
SEPARATION PROCESSES
SOLVOLYSIS
STEAM
SULFITES
SULFUR COMPOUNDS
TOLERANCE
USES
VACUUM DISTILLATION
WASTE WATER
WASTES
WATER
WOOD
WOOD PRODUCTS INDUSTRY
YEASTS
YIELDS