Methanosaeta fibers in anaerobic migrating blanket reactors

An anaerobic migrating blanket reactor (AMBR) was seeded with flocculent biomass from a digester and fed a substrate consisting of volatile fatty acids and sucrose to study granulation. After three months of operation, a mature granular blanket developed in the reactor. Moreover, fibers of approximately 1 cm long had become prevalent in the AMBR. Scanning electron microscopy (SEM) and light microscopy revealed a very dense structure consisting of bundles of filaments resembling Methanosaeta cells. Further studies with fluorescence in-situ hybridization (FISH), showed that Methanosaeta concilii was the predominant microorganism in these fibers.