Are some putative glycogen accumulating organisms (GAO) in anaerobic : aerobic activated sludge systems members of the α-Proteobacteria?

Beer, Michael; Kong, Yun; Seviour, Robert J.

doi:10.1099/mic.0.26825-0

Cited by 52 publications

(46 citation statements)

References 41 publications

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“…DF2MIX (Table 1) Defluvicoccus-related organisms accounted for an additional 8 % (SEM=1 %) of the Bacteria, and the cells that bound these probes were TFOs. The fact that the majority of Alphaproteobacteria in the biomass that cycled PHA did not bind the current probes for GAOs strongly suggests the presence of other GAOs, despite the similar morphology of these organisms to those described in the literature (Beer et al, 2004;Meyer et al, 2006;Wong et al, 2004). It may be that the probes from these publications do not target the diversity of the organisms within these already identified groups so that additional sequences are required in order to broaden the probe specificities; alternatively, another group of GAOs unrelated to Sphingomonas or D. vanus may exist.…”

Section: Fish and Post-fish Chemical Stainingmentioning

confidence: 65%

“…One group are members of the order Sphingomonadales, and the other is related to the isolate Defluvicoccus vanus within the order Rhodospirillales. Both of these organisms could consume acetate as the sole carbon source (Beer et al, 2004;Wong et al, 2004), but the D. vanus-related organism has also been recently demonstrated to consume propionate (Meyer et al, 2006), unlike Competibacter.…”

Section: Introductionmentioning

confidence: 99%

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Anaerobic and aerobic metabolism of glycogen-accumulating organisms selected with propionate as the sole carbon source

et al. 2006

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In the microbial competition observed in enhanced biological phosphorus removal (EBPR) systems, an undesirable group of micro-organisms known as glycogen-accumulating organisms (GAOs) compete for carbon in the anaerobic period with the desired polyphosphate-accumulating organisms (PAOs). Some studies have suggested that a propionate carbon source provides PAOs with a competitive advantage over GAOs in EBPR systems; however, the metabolism of GAOs with this carbon source has not been previously investigated. In this study, GAOs were enriched in a laboratory-scale bioreactor with propionate as the sole carbon source, in an effort to better understand their biochemical processes. Based on comprehensive solid-, liquid-and gas-phase chemical analytical data from the bioreactor, a metabolic model was proposed for the metabolism of propionate by GAOs. The model adequately described the anaerobic stoichiometry observed through chemical analysis, and can be a valuable tool for further investigation of the competition between PAOs and GAOs, and for the optimization of the EBPR process. A group of Alphaproteobacteria dominated the biomass (96 % of Bacteria) from this bioreactor, while postfluorescence in situ hybridization (FISH) chemical staining confirmed that these Alphaproteobacteria produced poly-b-hydroxyalkanoates (PHAs) anaerobically and utilized them aerobically, demonstrating that they were putative GAOs. Some of the Alphaproteobacteria were related to Defluvicoccus vanus (16 % of Bacteria), but the specific identity of many could not be determined by FISH. Further investigation into the identity of other GAOs is necessary.

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Section: Fish and Post-fish Chemical Stainingmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Anaerobic and aerobic metabolism of glycogen-accumulating organisms selected with propionate as the sole carbon source

et al. 2006

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“…FISH showed that Actinobacteria, mainly consisting of two probe-defined actinobacterial PAO groups, constituted 13 % of the bacterial biovolume, while no actinobacterial clone was retrieved in the clone library analysis. This could be due to the difficulty of extracting DNA from Gram-positive bacteria (Beer et al, 2004), PCR bias and/or low cloning number (Head et al, 1998).…”

Section: Discussionmentioning

confidence: 99%

Structure and function of the microbial community in a full-scale enhanced biological phosphorus removal plant

et al. 2007

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The structure and function of the microbial community in a full-scale enhanced biological phosphorus removal wastewater treatment plant (WWTP; Skagen) were investigated using the full-cycle rRNA approach, combined with ecophysiological studies. A total of 87 16S rRNA gene sequences were retrieved, and 78 operational taxonomic units were identified. Novel oligonucleotide probes were designed, and quantitative fluorescence in situ hybridization revealed that six hitherto undescribed probe-defined groups within the phylum Bacteroidetes (two groups), and classes Betaproteobacteria (two groups) and Gammaproteobacteria (two groups), were relatively abundant (.1 % of total biovolume) in the Skagen WWTP and 10 other full-scale WWTPs with biological P removal. The most abundant was a group of rod-shaped Bacteroidetes attached to filamentous bacteria, which is distantly related to the genus Haliscomenobacter of the family Saprospiraceae, and comprised 9-19 % of the bacterial biovolume in all the WWTPs investigated. The other five probe-defined groups were found in all WWTPs, but they were less abundant (1-6 %). Two groups had a glycogen-accumulating phenotype and one Dechloromonas-related group had a polyphosphate-accumulating phenotype, and they were potentially all involved in denitrification. In total, about 81 % of all bacteria hybridizing with the general eubacterial probe were detected in the Skagen WWTP by using clone-or group-specific probes, indicating that most members of the microbial community had been identified. INTRODUCTIONAn increasing number of wastewater treatment plants (WWTPs) are designed, or have been upgraded, to remove C, N and P by using microbial activity in the process known as enhanced biological phosphorus removal (EBPR). This process is popular mainly because it is more environmentally friendly, due to reduced use of chemicals and low sludge production, compared to P removal by chemical precipitation (Seviour et al., 2003). The general understanding of design and operation of activated-sludge WWTPs has increased significantly in the last two decades, but occasionally EBPR WWTPs still suffer from suboptimal operation and breakdown of the P-removal process. These problems are believed to be due to poor understanding of the structure of the microbial community in EBPR WWTPs and insufficient knowledge of the ecophysiology of the key microbial populations.Our understanding of the microbiology of EBPR WWTPs is to a large extent obtained from culture-independent studies using enriched cultures in well-controlled laboratory-scale reactors by using the full-cycle rRNA approach (Amann, 1995), as reviewed in detail by Mino et al. (1998) and Seviour et al. (2003). Some potentially important micro-organisms involved in the EBPR process have been identified in such laboratory-scale reactors, but only a few of them have been shown to be important in full-scale WWTPs. These are all uncultured organisms and can thus only be detected and quantified by using molecular methods such as fluorescence in situ hybrid...

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“…(Meyer et al, 2006), SBR9-1a for Alphaproteobacteria Sphingomonas spp. (Beer et al, 2004), PAOMIX (Crocetti et al, 2000) for the Betaproteobacteria Accumulibacter spp., and GAOMIX (equal amounts of GAOQ989 and GB_G2 Kong et al, 2002) for the Gammaproteobacteria Competibacter spp. All microscopic examinations were carried out using a Zeiss LSM510 Meta confocal laser scanning microscope (CLSM).…”

Section: Methodsmentioning

confidence: 99%

“…These organisms have been phylogenetically identified as closely related to the pure culture Defluviicoccus vanus (Meyer et al, 2006;Wong et al, 2004) and Sphingomonas spp. (Beer et al, 2004). Due to the nature of the lab-scale studies carried out by enrichment of microorganisms on sole organic carbon substrates, key aspects of their ecophysiology in full-scale plants are not known.…”

Section: Introductionmentioning

confidence: 99%

Abundance and ecophysiology of Defluviicoccus spp., glycogen-accumulating organisms in full-scale wastewater treatment processes

et al. 2007

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The activity of glycogen-accumulating organisms (GAOs) in enhanced biological phosphorus removal (EBPR) wastewater treatment plants has been proposed as one cause of deterioration of EBPR. Putative GAOs from the Alphaproteobacteria, Defluviicoccus spp. (including D. vanus), were studied in full-scale EBPR plants to determine their distribution, abundance and ecophysiology. Fluorescence in situ hybridization (FISH) demonstrated that Defluviicoccus spp. were generally low in abundance; however, in one plant surveyed, Cluster 2 Defluviicoccus constituted 9 % of all Bacteria. FISH combined with microautoradiography revealed that both Cluster 1 and Cluster 2 Defluviicoccus were capable of taking up a narrow range of substrates including acetate, propionate, pyruvate and glucose under anaerobic and aerobic conditions. Formate, butyrate, ethanol and several other substrates were not taken up. Cluster 2 Defluviicoccus demonstrated a phenotype consistent with the current metabolic model for GAOs -anaerobic assimilation of acetate and reduction to polyhydroxyalkanoates (PHA) using the glycolytic pathway, and aerobic consumption of PHA. Polyphosphate-accumulating organisms (PAOs, 'Candidatus Accumulibacter phosphatis') and other putative GAOs ('Candidatus Competibacter phosphatis') co-existed in two plants with Cluster 2 Defluviicoccus, but in both plants, the latter organisms were more abundant. Thus Cluster 2 Defluviicoccus can be relatively abundant and could be carbon competitors of PAOs and other GAOs in EBPR plants.

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Are some putative glycogen accumulating organisms (GAO) in anaerobic : aerobic activated sludge systems members of the α-Proteobacteria?

Cited by 52 publications

References 41 publications

Anaerobic and aerobic metabolism of glycogen-accumulating organisms selected with propionate as the sole carbon source

Anaerobic and aerobic metabolism of glycogen-accumulating organisms selected with propionate as the sole carbon source

Structure and function of the microbial community in a full-scale enhanced biological phosphorus removal plant

Abundance and ecophysiology of Defluviicoccus spp., glycogen-accumulating organisms in full-scale wastewater treatment processes

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