Efficient cellulose and hemicellulose utilization are essential for the economic conversion of lignocellulosics to ethanol. Spathaspora passalidarum, which is found in association with beetle guts, ferments both xylose and cellobiose, grows at up to 42°C and has a temperature optimum between 35°C and 37°C.  Moreover, its glucose and xylose utilization rates are comparable under aerobic and oxygen limiting conditions, which suggest that the basic sugar mechanisms are similar.  Glucose and xylose utilization differ under oxygen limited or anaerobic conditions during the fermentation of mixed sugars, however glucose represses xylose utilization only transiently.  Glucose is used faster initially, but both sugars are consumed simultaneously, which indicates a weak glucose repression mechanism and a strong glucose/xylose transport system.  Nicotinic and oleic acids are necessary for anaerobic growth of this organism.  These additives also improve fermentation of both glucose and xylose under severe oxygen limitation.  With xylose as the carbon source, ethanol was oxidized once a critical concentration was achieved, even while under oxygen limitation with excess sugar present.  This suggests that glucose does not repress respiration.  Nutritional supplementation reduces the oxidation of ethanol.  The capacity for growth at elevated temperatures, its ability to ferment both xylose and cellobiose and its ability to grow and ferment under severe oxygen limitation make S. passalidarum of significant interest for bioconversion.