Summary
Members of the uncultured bacterial genus
Candidatus
Accumulibacter are capable of intracellular accumulation of inorganic phosphate in activated sludge wastewater treatment plants (WWTPs) performing enhanced biological phosphorus removal, but were also recently shown to inhabit freshwater and estuarine sediments. Additionally, metagenomic sequencing of two bioreactor cultures enriched in
Candidatus
Accumulibacter, but housed on separate continents, revealed the potential for global dispersal of particular
Candidatus
Accumulibacter strains, which we hypothesize is facilitated by the ability of
Candidatus
Accumulibacter to persist in environmental habitats. In the current study, we used sequencing of a phylogenetic marker, the
ppk
1 gene, to characterize
Candidatus
Accumulibacter populations in diverse environments, at varying distances from WWTPs. We discovered several new lineages of
Candidatus
Accumulibacter which had not previously been detected in WWTPs, and also uncovered new diversity and structure within previously detected lineages. Habitat characteristics were found to be a key determinant of
Candidatus
Accumulibacter lineage distribution while, as predicted, geographic distance played little role in limiting dispersal on a regional scale. However, on a local scale, enrichment of particular
Candidatus
Accumulibacter lineages in WWTP appeared to impact local environmental populations. These results provide evidence of ecological differences among
Candidatus
Accumulibacter lineages.