Effect of nutrient addition on RaBIT fermentation process. Fermentation conditions consisted of 6% glucan loading hydrolysate, 32°C, initial pH of 6.0, and initial cell loading of 7.5 g/L DCW. Closed symbols represent xylose concentration; open symbols represent ethanol concentration. Tested were a) no nutrients or nutrient concentrations of 1 g/L (orange diamonds), 2.5 g/L (blue squares), and 5.0 g/L (green circles) using b) yeast extract, c) wheat germ, or d) corn steep liquor. Initial glucose and xylose concentrations were approximately 58 g/L and 29 g/L, respectively. Error bars are present for all data points, but may be hidden by the symbols.