Physiological Properties of a Mutant of Pachysolen tannophilus Deficient in NADPH-Dependent d-Xylose Reductase.
A d-xylose reductase mutant of Pachysolen tannophilus was isolated on the basis of its poor growth on d-xylose but normal growth on xylitol and d-glucose. Fractionation of cell extracts indicated that the mutant was deficient in d-xylose reductase activity that used NADPH exclusively as a cofactor, but not in activity that used both NADH and NADPH. Mutant cultures grown on d-xylose as the sole carbon source exhibited some properties that would be desired in improved strains. Growth rate, growth yield, and d-xylose consumption rate of the mutant were less sensitive than those of the wild type to changes in aeration rate. d-Xylose was utilized more efficiently in that less of a by-product, xylitol, was produced. In addition, under low aeration conditions, more ethanol was produced. A disadvantage was a relatively slow rate of d-xylose utilization.
Schneider
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Division of Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6, Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1, and Institut für Biochemische Technologie und Mikrobiologie, Abteilung für Mikrobielle Biochemie, Technische Universität Wien, A-1060 Vienna, Austria.
Lee
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Barbosa
M de F
Mde F
Kubicek
C P
CP
James
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