Lawrence Berkeley National Laboratory

Xylose is a major constituent of angiosperm lignocellulose, so its fermentation is important for bioconversion to fuels and chemicals. Pichia stipitis is the best-studied native xylose fermenting yeast. Genes from P. stipitis have been used to engineer xylose metabolism in Saccharomycescerevisiae, and the regulation of the P. stipitis genome offers insights into the mechanisms of xylose metabolism in yeasts. We have sequenced, assembled and finished the genome of P.stipitis. As such, it is one of only a handful of completely finished eukaryotic organisms undergoing analysis and manual curation. The sequence has revealed aspects of genome organization, numerous genes for biocoversion, preliminary insights into regulation of central metabolic pathways, numerous examples of co-localized genes with related functions, and evidence of how P. stipitis manages to achieve redox balance while growing on xylose under microaerobic conditions.