%0 Journal Article %A Beer, Michael %A Kong, Yun H. %A Seviour, Robert J. %T Are some putative glycogen accumulating organisms (GAO) in anaerobic : aerobic activated sludge systems members of the α-Proteobacteria? %D 2004 %J Microbiology, %V 150 %N 7 %P 2267-2275 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.26825-0 %K TFO, tetrad-forming organisms %K P, orthophosphate %K EBPR, enhanced biological phosphorus removal %K PAO, polyphosphate-accumulating organisms %K DGGE, denaturing gradient gel electrophoresis %K SBR, sequencing batch reactor %K GAO, glycogen-accumulating organisms %K FISH, fluorescence in situ hybridization %K PHA, poly-β-hydroxyalkanoates %I Microbiology Society, %X Activated sludge plants designed to remove phosphorus microbiologically often perform unreliably. One suggestion is that the polyphosphate-accumulating organisms (PAO) are out-competed for substrates by another group of bacteria, the glycogen-accumulating organisms (GAO) in the anaerobic zones of these processes. This study used fluorescence in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE) to analyse the communities from laboratory-scale anaerobic : aerobic sequencing batch reactors. Members of the genus Sphingomonas in the α-Proteobacteria were present in large numbers in communities with poor phosphorus removal capacity where the biomass had a high glycogen content. Their ability to store poly-β-hydroxyalkanoates anaerobically, but not aerobically, and not accumulate polyphosphate aerobically is consistent with these organisms behaving as GAO there. No evidence was found to support an important role for the γ-Proteobacteria as possible GAO in these communities, although these bacterial populations have been considered in other studies to act as possible competitors for the PAO. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.26825-0