The ethanol tolerance of Pachysolen tannophilus in fermentation on xylose.

The influence of ethanol on fermentation by Pachysolen tannophilus was studied. When xylose utilization rate was 80%, ethanol concentration began to decline. Fermentation of P. tannophilus was affected by ethanol addition in the beginning of fermentation; average xylose consumption rate was 0.065 g.l(-1).h(-1), and maximum specific growth rate was 0.07 h(-1) at 28 g.l(-1) ethanol, comparing with the average xylose consumption rate of 0.38 g.l(-1).h(-1) and maximum specific growth rate of 0.14 h(-1) in fermentation with no ethanol addition; P. tannophilus stopped growth at 40 g.l(-1) ethanol. When the initial ethanol concentration was 30 g.l(-1), the addition of glucose in xylose media made the growth of P. tannophilus better, and the most favorable glucose concentration was 15 g.l(-1) with the highest biomass of 1.51 g.l(-1) as compared with that of 0.95 g.l(-1) in pure xylose media.