INFLUENCE OF SUPPORT MATERIAL ON HYDROGEN PRODUCTION IN MESOPHILIC ACIDOGENIC PACKED BED REACTORS (APBR) FED WITH SUGARCANE VINASSE. BioHydrogen

Four types of materials of support: clay expanded (CE), charcoal (Ch), porous ceramic (PC) and low density polyethylene (LDP) were tested in anaerobic packed bed reactors to produce hydrogen using sugarcane vinasse. Four reactors (2.3 L) filled with the different support materials were operated in parallel at Hydraulic Retention Time of 24 h, Organic Loading Rate of 36.2 kg-COD.m-3.d-1 and 25°C. Hydrogen was only produced in the reactors filled with CE and LDP with maximum values of volumetric hydrogen production of 404 and 509.5 mL-H2.d-1.L-1reactor and yields of 2.6 and 3.2 mol-H2.mol-1carbohydrates total, respectively. 16S rRNA T-RFLP and scanning electron microscopy confirm the selection of different microbial populations. The production of hydrogen was instable and decreased after 15 days. 454 pyrosequencing performed in samples from the reactor fill with LCP revealed that hydrogen producing organisms (Clostridium and Pectinatus) predominate in the hydrogen production period while lactic acid bacteria and non-fermentative organisms predominate during null hydrogen production.