Ethanolic fermentation of pentoses in lignocellulose hydrolysates
- Lund Univ. Chemical Center (Sweden)
In the fermentation of lignocellulose hydrolysates to ethanol, two major problems are encountered: the fermentation of the pentose sugar xylose, and the presence of microbial inhibitors. Xylose can be directly fermented with yeasts; such as Pachysolen tannophilus, Candida shehatae, and Pichia stipis, or by isomerization of xylose to xylulose with the enzyme glucose (xylose) isomerase, and subsequent fermentation with bakers yeast, Saccharomyces cerevisiae. The direct fermentation requires low, carefully controlled oxygenation, as well as the removal of inhibitors. Also, the xylose-fermenting yeasts have a limited ethanol tolerance. The combined isomerization and fermentation with XI and S. cerevisiae gives yields and productivities comparable to those obtained in hexose fermentations without oxygenation and removal of inhibitors. However, the enzyme is not very stable in a lignocellulose hydrolysate, and S. cerevisiae has a poorly developed pentose phosphate shunt. Different strategies involving strain adaptation, and protein and genetic engineering adopted to overcome these different obstacles, are discussed.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Badger Engineers, Inc., Tampa, FL (United States); Solar Energy Research Inst., Golden, CO (United States)
- OSTI ID:
- 431574
- Report Number(s):
- CONF-900512-; TRN: 96:006510-0012
- Resource Relation:
- Conference: 12. symposium on biotechnology fuels and chemicals, Gatlinburg, TN (United States), 7-11 May 1990; Other Information: PBD: 1991; Related Information: Is Part Of Twelfth symposium on biotechnology for fuels and chemicals; Greenbaum, E. [ed.] [Oak Ridge National Lab., TN (United States)]; Wyman, C.E. [ed.] [Solar Energy Research Inst., Golden, CO (United States)]; PB: 934 p.
- Country of Publication:
- United States
- Language:
- English
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