 "S. stipitis" is distantly related to brewer's yeast, "Saccharomyces cerevisiae", which uses the conventional codon system.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.Xylose is a hemicellulosic sugar found in all angiosperm plants.