Fed-batch fermentations were performed in 4 L (LH Inceltech
Series 210) at 30 C with 1 vvh aeration and 150 rpm stirring speed (Fig. 2). Reactor feeding was made by a peristaltic pump (Gilson). As it is done in the industry, the fed-batch fermentations were divided in three phases: the first one was made in batch mode in a low gravity media for yeast propagation, the second one consisted in reactor feeding and corresponded to ethanol production and the third one was made in batch mode to exhaust as much sugar as possible. These phases are called: propagation phase, feeding phase and exhausting phase respectively (Fig. 2). Concentrations and durations of these
different phases are shown in Table 1.