CONSECUTIVE BATCH FERMENTATION PROCESS FOR VERY HIGH GRAVITY ETHANOL FERMENTATION WITH FLOCCULATING YEAST FL-20

The application of process engineering strategies for the development of high productivity fermentation systems is considered a key issue in the bioethanol industry. One strategy to increase the potential for ethanol production and to minimize the problems generated is the fermentation with high alcohol content that can be achieved through the use of more concentrated musts in total sugars (HGV). Associated with the VHG process, the use of yeast strains with flocculating characteristics is also economically feasible due to its simplicity and low cost, since it does not require separation of the cells by centrifugation and does not need support, as is the case of the immobilized cells. This work evaluates the behavior of the flocculent strain Saccharomyces cerevisiae FL-20 strain in repeated batch VHG fermentations. Using the modified FL-20 strain, repeated batch in 8 consecutive cycles, with recycle of the cells throughout the process, was obtained while the process was viable, ethanol concentration of 15.8 % (v/v) and ethanol yield of 0.416, 81.5% of its theoretical value of 0.511, with a final productivity of 2.66 g/Lh.