Ecophysiology of polyphosphate-accumulating organisms and glycogen-accumulating organisms in a continuously aerated enhanced biological phosphorus removal process.
OBJECTIVE
To investigate the ecophysiology of populations of polyphosphate-accumulating organisms (PAO) and glycogen-accumulating organisms (GAO) in communities of a novel acetate fed process removing phosphate from wastewater. Attempts were made to see if acetate could be replaced by an alternative carbon source which did not support the growth of the GAO.


RESULTS
A continuously aerated sequencing batch reactor was operated with different acetate feed levels. Fluorescence in situ hybridization (FISH) showed that Defluviicoccus GAO numbers increased at lower acetate feed levels. With FISH/microautoradiography (MAR) both detected morphotypes of Defluviicoccus assimilated a wider range of substrates aerobically than Accumulibacter PAO. Their uptake profile differed from that reported for the same phylotype in full scale anaerobic : aerobic EBPR plants.


CONCLUSIONS
This suggests that replacing acetate with another substrate is unlikely to provide Accumulibacter with a selective advantage in this process. Why Defluviicoccus appeared to out-compete Accumulibacter at lower acetate concentrations was not clear. Data suggest physiological and morphological diversity may exist within a single Defluviicoccus phylotype.


CONCLUSIONS
This study implies that the current FISH probes for Defluviicoccus GAO may not reveal the full extent of their biodiversity, and that more information is required before strategies for their control can be devised.
Biotechnology Research Centre, La Trobe University, Bendigo, Vic., Australia.
S
S
Schroeder
J
J
Ahn
R J
RJ
Seviour
D000085:Acetates / Q000378:metabolism*; D000332:Aerobiosis; D020561:Alphaproteobacteria / Q000378:metabolism*; D020562:Betaproteobacteria / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D004463:Ecology; D015180:Electrophoresis, Gel, Two-Dimensional; D006003:Glycogen / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014865:Waste Disposal, Fluid; D014871:Water Microbiology
D000085:Acetates; D012336:RNA, Ribosomal, 16S; D006003:Glycogen