Composite FISH image of activated sludge. Yellow = "Competibacteraceae"; Blue = "Ca. Accumulibacter"; Green = other cells. Scale bar = 10 microns. - Source:1Aerobic heterotroph
The originally defined "Ca. Competibacter" genus has been split. What was originally known as sub-group GB1 has essentially been redefined to represent the genus "Ca. Competibacter" 2. In situ behaviour is consistent with the GAO phenotype and they are thought to compete with the PAO for resources with their proliferation at the theoretical expense of EBPR efficiency 3 4. Members from the genus have not been demonstrated to denitrify in situ, utilizing nitrate, but not nitrite as an electron acceptor 3. It is suggested to supply nitrite in anoxic conditions to PAO for P-uptake in a partly syntrophic relationship 8. However, genomic analysis of the species “Ca. C. denitrificans” indicates the potential for full denitrification to nitrogen 2. Members also appear to vary in their ability to assimilate thymidine and to ferment glucose, with single cell in situ analysis 3 2. Genome analysis of “Ca. C. denitrificans” reveals the potential for fermentation of glucose, and glycolysis via the Entner-Doudoroff (ED) and Embden-Mayerhof-Parnas (EMP) pathways.
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