Fermentation of lignocellulosic sugars to ethanol: selection of mutants of Pichia stipitis affected for D-glucose utilization.

Abstract Mutants of the xylose-fermenting yeast Pichia stipitis exhibiting a decreased ability to convert glucose to ethanol were obtained by mutagenesis with UV light. Mutants were isolated by replica-plating onto complete medium containing either d - galactose or d - glucose as carbon source. Mutants showing a reduction of growth on glucose were further tested for their ability to still use xylose. Finally, the kinetic behavior of six mutant strains grown on glucose and xylose is presented.