초록
Two continuous anaerobic fluidized bed reactors (AFBRs) were operated under thermophilic (55 <SUP>o</SUP>C) temperature for 150 days to investigate the effect of dark H<SUB>2</SUB> fermentation of diluted and raw sugarcane vinasse on H<SUB>2</SUB> production using mixed seed sludge. Although effective H<SUB>2</SUB> production (52.8% of H<SUB>2</SUB>; 0.80 L H<SUB>2</SUB> h<SUP>-1</SUP> L<SUP>-1</SUP>; 0.79 mmol gCOD<SUB>added</SUB><SUP>-1</SUP>) was observed using an elevated substrate concentration (30,000 mg COD L<SUP>-1</SUP>), the optimal operational conditions were found for the AFBR<SUB>1</SUB> (10,000 mg COD L<SUP>-1</SUP>) fed with diluted sugarcane vinasse (HRT 6 h; OLR 40 kg COD m<SUP>-3</SUP> d<SUP>-1</SUP>), achieving a H<SUB>2</SUB> yield of 2.86 mmol H<SUB>2</SUB> g COD<SUB>added</SUB><SUP>-1</SUP>. H<SUB>2</SUB> production was inhibited by elevated volatile fatty acid (VFA) concentrations (butyric and acetic acids = 3.7 and 3.0 g L<SUP>-1</SUP>, respectively) in the raw feedstock. Denaturing gradient gel electrophoresis (DGGE) analyses revealed changes in the bacterial population of the expanded clay biofilm as a function of the substrate concentration.