Yeasts of biotechnological, taxonomic and physiological interest

An osmotolerant yeast with the rare ability to ferment D-xylose to ethanol known in fewer than 10 species. Uniquely, it also uses nitrate. This species is only distantly related to other xylose fermenters and will be useful in tracking changes among xylose fermenters. Scheffersomyces (Pichia) stipitis NRRL Y-7124 (Type) has shown substantial physiological differences from the previously sequenced strain CBS 6054 (e.g, reported xylanase activity not present in CBS 6054 and differences in cellobiose utilization). We hope to identify additional sugar transporters and understand better the regulatory differences that enable one of these two strains to ferment xylose faster, and the other to be able to ferment cellobiose faster. The yeast has a holdfast, an unusual structure in yeasts when it grows attached to the gut of wood-ingesting beetles.