Genetic and biochemical characterization of mutations affecting the ability of the yeast Pachysolen tannophilus to metabolize D-xylose
- National Research Council of Canada, Ottawa, Ontario (Canada)
Induced mutants, selected for their defective growth on D-xylose while retaining the ability to grow normally on D-glucose, were studied in Pachysolen tannophilus, a yeast capable of converting D-xylose to ethanol. Fourteen of the mutations were found to occur at nine distinct loci, and data indicated that many more loci remain to be detected. Most of the mutations were pleiotropic in character, and the expression of some of them was much affected by nutritional conditions and by genetic background. Mutations at several loci resulted in poor growth on at least one compound that was either an intermediate of the tricarboxylic acid cycle, succinate or {alpha}-ketoglutarate, or on compounds metabolizable via this cycle, ethanol or glycerol. An initial biochemical characterization of the mutants was undertaken. Analysis for xylose reductase, xylitol dehydrogenase, and xylulose kinase activity showed that one or more of these activities was affected in 12 of 13 mutants. However, drastic reduction in activity of a single enzyme was confined to that of xylitol dehydrogenase by mutations at three different loci and to that of D-xylose reductase by mutation at another locus. Growth of these latter four mutants was normal on all carbon sources tested that were not five-carbon sugars.
- OSTI ID:
- 5962290
- Journal Information:
- Applied and Environmental Microbiology; (USA), Journal Name: Applied and Environmental Microbiology; (USA) Vol. 55:11; ISSN 0099-2240; ISSN AEMID
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
090900* -- Biomass Fuels-- Processing-- (1990-)
ALCOHOLS
ALDEHYDES
BIOLOGY
BIOSYNTHESIS
CARBOHYDRATES
ENZYME ACTIVITY
ETHANOL
EUMYCOTA
FUNGI
GENETICS
HYDROXY COMPOUNDS
METABOLISM
MICROORGANISMS
MONOSACCHARIDES
MUTANTS
ORGANIC COMPOUNDS
PENTOSES
PLANTS
SACCHARIDES
SYNTHESIS
XYLOSE
YEASTS