THERMOPHILIC HYDROGEN PRODUCTION IN ACIDOGENIC PACKED BED REACTOR (APBR) FED WITH SUGARCANE VINASSE: PERFORMANCE DURING LONG-TERM OPERATION. BioHydrogenThermophilic

This study aimed to evaluate the long-term operation of an up-flow anaerobic packed bed reactor (APBR) filled with low-density of polyethylene (LDP) and applied to thermophilic hydrogen production using sugarcane vinasse as substrate. The APBR was operated at organic loading rate (OLR) of 84.2 kg-COD.m-3.d-1, value determined in earlier study. The maximum values of hydrogen production and yield were 5,252.6 mL-H2.d-1 and 3.7 mol-H2.mol-1total carbohydrates, respectively. However, as the OLR applied was constant, the values of specific organic load rate (sOLR) decreased throughout operation from values from 1.38 to 0.72 g-Total carbohydrates.g-VS-1.h-1, thus, interfering negatively on hydrogen production. sOLR values around 1.22 g-Total carbohydrates.g-VS-1.h-1 indicated optimal conditions for hydrogen production. The microbial community was study by 454-pyrosequencing analysis. Organisms belonging to genera Caloramotor, Clostridium, Thermoanaerobacterium, Thermohydrogenium, Caldanaerobius and Megasphaera were detected in samples taken from reactor at days 30 and 60 of operation, suggesting a role in the hydrogen production.