Diversity of comammox bacteria in wastewater.

The overall objective of this study was to test the hypothesis that the widespread distribution and persistence of nearly identical comammox bacterial population in multiple secondary wastewater treatment systems was due to the presence of large number of co-existing strains (i.e., high microdiversity). To accomplish this, we used a combination of full-length 16S rRNA gene sequencing and hybrid metagenome assembly and binning approach to systematically explore the population and strain level diversity of nitrifiers in three full-scale nitrogen removal systems with different process configurations. In doing so, we also aimed to assess factors that may influence the population and intra-population diversity of co-existing nitrifiers.