The aim of this work was to investigate the anaerobic biomass formation capable of treating vinasse from the
production of sugar cane alcohol, which was evolved within an anaerobic sequencing batch biofilm reactor
(ASBBR) as immobilized biomass on cubes of polyurethane foam at the temperature of 55ºC. The reactor was
inoculated with mesophilic granular sludge originally treating poultry slaughterhouse wastewater. The evolution of
the biofilm in the polyurethane foam matrices was assessed during seven experimental phases which were thus
characterized by the changes in the organic matter concentrations as COD (1.0 to 20.0 g/L). Biomass
characterization proceeded with the examination of sludge samples under optical and scanning electron
microscopy. The reactor showed high microbial morphological diversity along the trial. The predominance of
Methanosaeta-like cells was observed up to the organic load of 2.5 gCOD/L.d. On the other hand, Methanosarcinalike
microorganisms were the predominant archaeal population within the foam matrices at high organic loading
ratios above 3.3 gCOD/L.d. This was suggested to be associated to a higher specific rate of acetate consumption by
the later organisms.
