Summary: Methanosaeta fibers in anaerobic migrating
L.T. Angenent,* D. Zheng,* S. Sung** and L. Raskin*
*Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 3221
Newmark, 205 N. Mathews, Urbana, IL 61801, U.S.A.
**Department of Civil and Construction Engineering, Iowa State University, 394 Town Engineering Building,
Ames, IA 50011, U.S.A.
Abstract 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.
Keywords Anaerobic migrating blanket reactor; AMBR; fibers; oligonucleotide hybridization probes;
ribosomal RNA; Methanosaeta
During the last 30 years, anaerobic systems that rely on the separation of solids retention
time (SRT) from hydraulic retention time (HRT) have proven to be sustainable.
Particularly, the upflow anaerobic sludge blanket (UASB) process, and its derivatives, have