Fucose and GlcNAc have been found only in Dictyostelium discoideum, mannose in Leishmania mexicana, and xylose in Trypanosoma cruzi.
Found, among other places, in the guts of passalid beetles, S. stipitis is capable of both aerobic and oxygen limited fermentation, and has the highest known natural ability of any yeast to directly ferment xylose, converting it to ethanol, a potentially economically valuable trait.
This can be accomplished either by native xylose fermenting yeasts such as Scheffersomyces Pichia stipitis or by metabolically engineered strains of Saccharomyces cerevisiae.
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In attempts to generate S. cerevisiae strains that are able to ferment D-xylose the XYL1 and XYL2 genes of P. stipitis coding for the D-xylose reductase (XR) and xylitol dehydrogenase (XDH), respectively were introduced in S. cerevisiae by means of genetic engineering.