Hydrogen and organic acid production by cultures of C. saccharolyticus and T. neapolitana grown on Miscanthus hydrolysate. (a) and (c) C. saccharolyticus. (b) and (d) T. neapolitana. (a) and (b) Hydrogen production. (c) and (d) Organic acid (acetic and lactic acid) production. Measurements were done after 16 and 40 h after the start of the fermentation. Hydrolysate concentration is given in g monosaccharides l-1. In the control without hydrolysate, 10 g l-1 of a glucose/xylose (7:3, w w-1) mixture was used as the carbon source. The error bars show the range about the mean of the values from two flasks.