PMID- 17704280
OWN - NLM
STAT- MEDLINE
DCOM- 20080122
LR  - 20181113
IS  - 0099-2240 (Print)
IS  - 1098-5336 (Electronic)
IS  - 0099-2240 (Linking)
VI  - 73
IP  - 19
DP  - 2007 Oct
TI  - Microbial composition and structure of aerobic granular sewage biofilms.
PG  - 6233-40
AB  - Aerobic activated sludge granules are dense, spherical biofilms which can 
      strongly improve purification efficiency and sludge settling in wastewater 
      treatment processes. In this study, the structure and development of different 
      granule types were analyzed. Biofilm samples originated from lab-scale sequencing 
      batch reactors which were operated with malthouse, brewery, and artificial 
      wastewater. Scanning electron microscopy, light microscopy, and confocal laser 
      scanning microscopy together with fluorescence in situ hybridization (FISH) 
      allowed insights into the structure of these biofilms. Microscopic observation 
      revealed that granules consist of bacteria, extracellular polymeric substances 
      (EPS), protozoa and, in some cases, fungi. The biofilm development, starting from 
      an activated sludge floc up to a mature granule, follows three phases. During 
      phase 1, stalked ciliated protozoa of the subclass Peritrichia, e.g., Epistylis 
      spp., settle on activated sludge flocs and build tree-like colonies. The stalks 
      are subsequently colonized by bacteria. During phase 2, the ciliates become 
      completely overgrown by bacteria and die. Thereby, the cellular remnants of 
      ciliates act like a backbone for granule formation. During phase 3, smooth, 
      compact granules are formed which serve as a new substratum for unstalked ciliate 
      swarmers settling on granule surfaces. These mature granules comprise a dense 
      core zone containing bacterial cells and EPS and a loosely structured fringe zone 
      consisting of either ciliates and bacteria or fungi and bacteria. Since granules 
      can grow to a size of up to several millimeters in diameter, we developed and 
      applied a modified FISH protocol for the study of cryosectioned biofilms. This 
      protocol allows the simultaneous detection of bacteria, ciliates, and fungi in 
      and on granules.
FAU - Weber, S D
AU  - Weber SD
AD  - Lehrstuhl fur Mikrobiologie, Technische Universitat Munchen, Am Hochanger 4, 
      85350 Freising, Germany. weber@mikro.biologie.tu-muenchen.de
FAU - Ludwig, W
AU  - Ludwig W
FAU - Schleifer, K-H
AU  - Schleifer KH
FAU - Fried, J
AU  - Fried J
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20070817
PL  - United States
TA  - Appl Environ Microbiol
JT  - Applied and environmental microbiology
JID - 7605801
RN  - 0 (Sewage)
SB  - IM
EIN - Appl Environ Microbiol. 2008 Jan;74(1):343
MH  - Aerobiosis
MH  - Animals
MH  - Bacteria, Aerobic/*physiology
MH  - Biofilms/*growth & development
MH  - Bioreactors/*microbiology
MH  - Ciliophora/isolation & purification/*physiology
MH  - In Situ Hybridization, Fluorescence
MH  - Population Dynamics
MH  - Sewage/*chemistry/*microbiology
MH  - Waste Disposal, Fluid/methods
PMC - PMC2075015
EDAT- 2007/08/21 09:00
MHDA- 2008/01/23 09:00
PMCR- 2008/02/01
CRDT- 2007/08/21 09:00
PHST- 2007/08/21 09:00 [pubmed]
PHST- 2008/01/23 09:00 [medline]
PHST- 2007/08/21 09:00 [entrez]
PHST- 2008/02/01 00:00 [pmc-release]
AID - AEM.01002-07 [pii]
AID - 1002-07 [pii]
AID - 10.1128/AEM.01002-07 [doi]
PST - ppublish
SO  - Appl Environ Microbiol. 2007 Oct;73(19):6233-40. doi: 10.1128/AEM.01002-07. Epub 
      2007 Aug 17.