TABLE 1.

Physiological characteristics of Paracoccus denitrificans and PAOs

Organism(s)	Anaerobic metabolism	Aerobic/anoxic metabolism	References
P. denitrificans	Unable to use external carbon source for PHA synthesis; degrades glycogen for PHA synthesis; degrades polyphosphate, releases phosphate; degradation of polyphosphate provides energy for growth	Produces polyphosphate and grows on energy provided by external carbon source; produces glycogen; in absence of external carbon source, cells with PHA do not grow and do not produce polyphosphate	7, 13, this study
PAOs	Use external carbon source for PHA synthesis; release phosphate; degrade polyphosphate; degrade glycogen	Produce polyphosphate by degradation of PHA, produce glycogen; grow in absence of external carbon source on PHA; when present, external carbon source might inhibit polyphosphate synthesis or is used for PHA production but not for growth	5, 11, 14, 17, 22