Morphological observation and microbial population dynamics in anaerobic polyurethane foam biofilm degrading gelatin

Abstract

-This work reports on a preliminary study of anaerobic degradation of gelatin with emphasis on the development of the proteolytic biofilm in polyurethane foam matrices in differential reactors. The evolution of the biofilm was observed during 22 days by optical and scanning electron microscopy (SEM) analyses. Three distinct immobilization patterns could be observed in the polyurethane foam: cell aggregates entrapped in matrix pores, thin biofilms attached to inner polyurethane foam surfaces and individual cells that have adhered to the support. Rods, cocci and vibrios were observed as the predominant morphologies of bacterial cells. Methane was produced mainly by hydrogenothrophic reactions during the operation of the reactors.

Influence of the carbon source on the anaerobic biomass adhesion on polyurethane foam matrices

“…10 (a-randomly distributed cells attached individually to the polyurethane surface; b-small multi-cellular structures attached to the inner polyurethane surface, where cells were attached to each other and linked by EPS; c-microgranules, probably immobilized mechanically or originating from an advanced colonization phase) were observed in all the experiments, indicating that the substrate did not influence the polyurethane foam colonization patterns. The same patterns had already been observed previously for glucose-based substrate (Varesche et al, 1997) and for protein-based substrate (Tommaso et al, 2002).…”

“…Three distinct biomass immobilization patterns were identified on the polyurethane surface, as observed in other studies using polyurethane foam as the support matrix (Varesche et al, 1997;Tommaso et al, 2002). The immobilization patterns illustrated in Fig.…”

Influence of Extracellular Polymeric Substances on Anaerobic Biofilms Supported by Polyurethane Foam Matrices

“…Several polymeric supports can be applied for biofilm growth in anaerobic reactors: acrilanamide (Inamori et al, 1989); polypropilene, polyethylene, polyacetal, polyamide (Verrier et al, 1987); polyvinyl chloride (Verrier et al, 1987;Picanço et al, 2001); polyurethane foam (Huysman et al, 1983;Calzada et al, 1984;Fynn et al, 1984;Gizgen et al, 1988;Foresti et al, 1995;Varesche et al, 1997;Zaiat et al, 1997;Picanço et al, 2001;Tommaso et al, 2002).…”

“…The reactors were maintained at 25°C inside a chamber provided with thermal control. This experimental apparatus was first used to estimate kinetic parameters and later on for evaluation of microbial adhesion dynamics (Tommaso et al, 2002). Macerated sludge from an UASB reactor treating poultry slaughterhouse wastewater was added daily to the substrate (300 mg SSV?L 21 ), which was changed daily.…”

Maximizing the productivity of catalytic biofilms on solid supports in membrane aerated reactors

“…strain VLB120DC showed good adherence towards all particle based packing materials. The large open pore structure exhibited by Basotect 1 and Poraver glass beads might have facilitated entrapment and colonization of the cells on the surface and inside the matrix (Messing and Oppermann, 1979;Pereira et al, 2000;Tommaso et al, 2002;Varesche et al, 1997). However, the pore geometry is not the only criterion for biofilm establishment.…”