Glycogen-accumulating organisms in laboratory-scale and full-scale wastewater treatment processes.
Laboratory-scale sequencing batch reactors (SBRs) as models for wastewater treatment processes were used to identify glycogen-accumulating organisms (GAOs), which are thought to be responsible for the deterioration of enhanced biological phosphorus removal (EBPR). The SBRs (called Q and T), operated under alternating anaerobic-aerobic conditions typical for EBPR, generated mixed microbial communities (sludges) demonstrating the GAO phenotype. Intracellular glycogen and poly-beta-hydroxyalkanoate (PHA) transformations typical of efficient EBPR occurred but polyphosphate was not bioaccumulated and the sludges contained 1.8% P (sludge Q) and 1.5% P (sludge T). 16S rDNA clone libraries were prepared from DNA extracted from the Q and T sludges. Clone inserts were grouped into operational taxonomic units (OTUs) by restriction fragment length polymorphism banding profiles. OTU representatives were sequenced and phylogenetically analysed. The Q sludge library comprised four OTUs and all six determined sequences were 99.7% identical, forming a cluster in the gamma-Proteobacteria radiation. The T sludge library comprised eight OTUs and the majority of clones were Acidobacteria subphylum 4 (49% of the library) and candidate phylum OP10 (39% of the library). One OTU (two clones, of which one was sequenced) was in the gamma-Proteobacteria radiation with 95% sequence identity to the Q sludge clones. Oligonucleotide probes (called GAOQ431 and GAOQ989) were designed from the gamma-Proteobacteria clone sequences for use in fluorescence in situ hybridization (FISH); 92% of the Q sludge bacteria and 28% of the T sludge bacteria bound these probes in FISH. FISH and post-FISH chemical staining for PHA were used to determine that bacteria from a novel gamma-Proteobacteria cluster were phenotypically GAOs in one laboratory-scale SBR and two full-scale wastewater treatment plants. It is suggested that the GAOs from the novel cluster in the gamma-Proteobacteria radiation be named 'Candidatus Competibacter phosphatis'.
Crocetti
Gregory R
GR
Advanced Wastewater Management Centre, The University of Queensland, St Lucia 4072, Australia1.
Banfield
Jillian F
JF
Department of Geology and Geophysics, University of Wisconsin-Madison, Madison, WI 53706, USA2.
Keller
Jürg
J
Advanced Wastewater Management Centre, The University of Queensland, St Lucia 4072, Australia1.
Bond
Philip L
PL
School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK3.
Blackall
Linda L
LL
Advanced Wastewater Management Centre, The University of Queensland, St Lucia 4072, Australia1.
D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism*; D017404:In Situ Hybridization, Fluorescence; D010641:Phenotype; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D012722:Sewage / Q000382:microbiology*; D013194:Staining and Labeling; D014865:Waste Disposal, Fluid; D018505:Waste Management; D018508:Water Purification
D012336:RNA, Ribosomal, 16S; D012722:Sewage; D006003:Glycogen