Effect of glucose supplements on the fermentation of xylose by Pachysolen tannophilus
Hemicellulosic sugars, predominantly D-xylose, comprise about one-half the total carbohydrate that can be obtained from hardwoods and agricultural residues through dilute acid hydrolysis. Because rates and yields in the xylose fermentation are low, economic utilization of these materials as fermentation feedstocks is difficult. Pachysolen tannophilus formed 5.5% ethanol from 12% glucose but only 2% ethanol from 12% xylose. Aeration doubled the specific rate of D-glucose fermentation by P. tannophilus, as compared to anaerobic fermenation, but the specific rate of the xylose fermentation remained unchanged. Periodic additions of 0.5% D-glucose to aerobic fermentations of 3% xylose increased the yield of ethanol from 0.28 g/g xylose to greater than 0.41 g/g xylose utilized. The rate of xylose utilization remained unchanged, and radiotracer studies showed that addition of 0.5% glucose did not inhibit xylose utilization under aerobic or anaerobic conditions. No enhancement was observed anaerobically, nor was enhancement observed with acid hydrolysates, apparently because of the presence of acetic acid which inhibited growth and fermentation.
- Research Organization:
- Dept. of Agriculture, Madison, WI
- OSTI ID:
- 5675711
- Journal Information:
- Biotechnol. Bioeng.; (United States), Journal Name: Biotechnol. Bioeng.; (United States) Vol. 27:2; ISSN BIBIA
- Country of Publication:
- United States
- Language:
- English
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Xylose fermentation to ethanol by Pachysolen tannophilus
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ACETIC ACID
ACID HYDROLYSIS
AERATION
ALCOHOLS
ALDEHYDES
BIOCONVERSION
CARBOHYDRATES
CARBOXYLIC ACIDS
CHEMICAL FEEDSTOCKS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
DECOMPOSITION
ETHANOL
FERMENTATION
FUNGI
GLUCOSE
GROWTH
HEXOSES
HYDROLYSIS
HYDROXY COMPOUNDS
LYSIS
MICROORGANISMS
MONOCARBOXYLIC ACIDS
MONOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PENTOSES
PLANTS
PRODUCTION
RESIDUES
RESPONSE MODIFYING FACTORS
SACCHARIDES
SOLVOLYSIS
WOOD
XYLOSE
YEASTS
YIELDS