Home • Spathaspora passalidarum NRRL Y-27907 v2.0
Photo of Spathaspora passalidarum NRRL Y-27907 v2.0
Courtesy of Thomas Kuster at USDA, Forest Products Lab

The Pichia stiptis-like yeasts Candida tenuis and Spathaspora passalidarum represent two members of a small group of yeasts that, like P. stipitis, can both ferment and assimilate xylose. Efficient fermentation of xylose, a five-carbon sugar that is a major component of plant cell walls, is a major step towards effective biofuel production from plant materials. Therefore, an increased understanding of the molecular mechanisms controlling xylose fermentation in fungi will be gained from comparative study of the genomes of P. stipitis, C. tenuis, and S. passalidarum. This work, in collaboration with the DOE Great Lakes Bioenergy Research Center (GLBRC), will help further the DOE's mission of removing bottlenecks in the biofuels pipeline, and increasing the availability of products produced from renewable plant biomass. C. tenuis and S. passalidarum were chosen for this study because they have xylose fermentation capacities that are comparable to P. stipitis under certain conditions. Furthermore, preliminary sequencing results suggest that the similarity of these three species is such that phylogenetic footprinting and ortholog comparisons will be possible. Although the discovery of S. passalidarum as a xylose fermenting fungi is relatively recent, it was chosen for sequencing based on our assessment that this species will be the most powerful in understanding the P. stipitis genome through comparative genomics. On the other hand, C. tenuis has been recognized for its xylose fermenting capacity for many years, and its xylose reductase enzymes have been studied. Consequently, a community of C. tenuis researchers exists who would greatly benefit from the genome sequence of this organism. Finally, C. tenuis and S. passalidarum are also unusual in that they are found in symbiotic association with wood-boring beetles, and comparative study may give new insight into the genetic underpinnings of symbiotic relationships.

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