skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Xylose fermentation: Analysis, modelling, and design

Abstract

Ethanolic fermentation is a means of utilizing xylose-rich industrial wastes, but an optimized bioprocess is lacking. Pachysolen tannophilus NRRL Y-7124 was the first yeast discovered capable of significant ethanol production from xylose and has served as a model for studies of other yeasts mediating this conversion. However, a comparative evaluation of strains led the authors to focus on Pichia stipitis NRRL Y-7124 as the yeast with highest potential for application. Given 150 g/l xylose in complex medium, strain Y-7124 functioned optimally at 25-26C pH 4-7 to accumulate 56 g/l ethanol with negligible xylitol production. Dissolved oxygen concentration was critical to cell growth; and in order to measure it accurately, a colorimetric assay was developed to allow calibration of electrodes based on oxygen solubility in media of varying composition. Specific growth rate was a Monod function of limiting substrate concentration (oxygen and/or xylose). Both specific ethanol productivity and oxygen uptake rate were growth-associated, but only the former was maintenance-associated. Both growth and fermentation were inhibited by high xylose and ethanol concentrations. Carbon and cofactor balances supported modelling xylose metabolism as a combination of four processes: assimilation, pentose phosphate oxidation, respiration, and ethanolic fermentation. A mathematical model describing the stoichiometry and kineticsmore » was constructed, and its predictive capacity was confirmed by comparing simulated and experimental batch cultures. Consideration of example processes indicated that this model constitutes an important tool for designing the optimum bioprocess for utilizing xylose-rich wastes.« less

Authors:
Publication Date:
Research Org.:
Purdue Univ., Lafayette, IN (United States)
OSTI Identifier:
7097019
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; ETHANOL; BIOSYNTHESIS; XYLOSE; FERMENTATION; BATCH CULTURE; BIOCHEMICAL REACTION KINETICS; GROWTH; INHIBITION; MATHEMATICAL MODELS; ORGANIC WASTES; OXYGEN; PENTOSES; PH VALUE; PRODUCTIVITY; STOICHIOMETRY; YEASTS; ALCOHOLS; ALDEHYDES; BIOCONVERSION; CARBOHYDRATES; ELEMENTS; EUMYCOTA; FUNGI; HYDROXY COMPOUNDS; KINETICS; MICROORGANISMS; MONOSACCHARIDES; NONMETALS; ORGANIC COMPOUNDS; PLANTS; REACTION KINETICS; SACCHARIDES; SYNTHESIS; WASTES; 090900* - Biomass Fuels- Processing- (1990-)

Citation Formats

Slininger, P J.W. Xylose fermentation: Analysis, modelling, and design. United States: N. p., 1988. Web.
Slininger, P J.W. Xylose fermentation: Analysis, modelling, and design. United States.
Slininger, P J.W. Fri . "Xylose fermentation: Analysis, modelling, and design". United States.
@article{osti_7097019,
title = {Xylose fermentation: Analysis, modelling, and design},
author = {Slininger, P J.W.},
abstractNote = {Ethanolic fermentation is a means of utilizing xylose-rich industrial wastes, but an optimized bioprocess is lacking. Pachysolen tannophilus NRRL Y-7124 was the first yeast discovered capable of significant ethanol production from xylose and has served as a model for studies of other yeasts mediating this conversion. However, a comparative evaluation of strains led the authors to focus on Pichia stipitis NRRL Y-7124 as the yeast with highest potential for application. Given 150 g/l xylose in complex medium, strain Y-7124 functioned optimally at 25-26C pH 4-7 to accumulate 56 g/l ethanol with negligible xylitol production. Dissolved oxygen concentration was critical to cell growth; and in order to measure it accurately, a colorimetric assay was developed to allow calibration of electrodes based on oxygen solubility in media of varying composition. Specific growth rate was a Monod function of limiting substrate concentration (oxygen and/or xylose). Both specific ethanol productivity and oxygen uptake rate were growth-associated, but only the former was maintenance-associated. Both growth and fermentation were inhibited by high xylose and ethanol concentrations. Carbon and cofactor balances supported modelling xylose metabolism as a combination of four processes: assimilation, pentose phosphate oxidation, respiration, and ethanolic fermentation. A mathematical model describing the stoichiometry and kinetics was constructed, and its predictive capacity was confirmed by comparing simulated and experimental batch cultures. Consideration of example processes indicated that this model constitutes an important tool for designing the optimum bioprocess for utilizing xylose-rich wastes.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1988},
month = {1}
}

Miscellaneous:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that may hold this item.

Save / Share: