Viral composition and context in metagenomes from biofilm and suspended growth municipal wastewater treatment plants

Abstract

Summary Wastewater treatment plants (WWTPs) contain high density and diversity of viruses which can significantly impact microbial communities in aquatic systems. While previous studies have investigated viruses in WWTP samples that have been specifically concentrated for viruses and filtered to exclude bacteria, little is known about viral communities associated with bacterial communities throughout wastewater treatment systems. Additionally, differences in viral composition between attached and suspended growth wastewater treatment bioprocesses are not well characterized. Here, shotgun metagenomics was used to analyse wastewater and biomass from transects through two full‐scale WWTPs for viral composition and associations with bacterial hosts. One WWTP used a suspended growth activated sludge bioreactor and the other used a biofilm reactor (trickling filter). Myoviridae, Podoviridae and Siphoviridae were the dominant viral families throughout both WWTPs, which are all from the order Caudovirales. Beta diversity analysis of viral sequences showed that samples clustered significantly both by plant and by specific sampling location. For each WWTP, the overall bacterial community structure was significantly different than community structure of bacterial taxa associated with viral sequences. These findings highlight viral community composition in transects through different WWTPs and provide context for dsDNA viral sequences in bacterial communities from these systems.

Genomic Characteristics Distinguish Geographically Distributed Dehalococcoidia

“…The immense number of viruses and viral particles that populate marine environments have a tremendous effect on microbial diversity directly (e.g., selectively killing of microorganisms) and indirectly (e.g., genetic material cycling, horizontal gene transfer) (Suttle, 2007;Cai et al, 2019). Of note, the high virus abundance in ecosystems such as a wastewater treatment plant may also play a role in the acquisition of mobile genetic elements in the genome of Dhc strain 195 (Seshadri et al, 2005;Petrovich et al, 2019). Therefore, experimental evidence and in silico analyses are still required to unravel the mechanisms leading to comparatively more horizontally transferred genes in the Dia marine genomes.…”

On uncovering and understanding interactions between bacteriophages and bacteria

“…The experiments laid out in this study identified 26 phage-host interactions in a hospital wastewater virome. Most of these were predictions of phages adsorbing to Proteobacteria, which is consistent with recent findings that these bacteria are ubiquitous and abundant in global waste water communities 277,278 . Several of the putative adsorbing viral populations represented rare members of the sampled hospital wastewater virome.…”

“…Notably, 22 of the 26 selected viral populations putatively adsorb to Proteobacteria cell envelopes, consistent with recent findings that Proteobacteria are the dominant bacterial phylum in global wastewater treatment plant microbiomes and are abundant in wastewater influent 277,278 . It is thus likely that Proteobacteria phages are common in wastewater microbiomes, which supports our findings.…”

SARS-CoV-2 in environmental perspective: Occurrence, persistence, surveillance, inactivation and challenges

“…Wastewater treatment plants (WWTPs), in general, have high density and diversity of viruses [72] . Human enteric viruses studied (rotavirus and enterovirus) in the final effluents of five WWTPs showed the persistence of Rotavirus (up to 10 5 genome copies (GC)/L in 41.7% of the samples) [73] .…”

“…Avian influenza virus (H6N2) survived in methanogenic landfill leachates and water showed rapid inactivation at elevated temperature and non-neutral pH while conductivity did not show any influence on the survival [76] . Viruses abundance in wastewater streams also influenced the bacterial community structure and catalyzed virus-mediated horizontal gene transfer [72] . Bacteriophages associated with the human GI tract are commonly reported in wastewater and phages infecting Bacteroides are used as an indicator for assessing the wastewater quality and contamination [77] .…”