Pathogenesis gene sets are enriched on plastic surfaces in wastewater

We established a genome-resolved time-series, beginning at one hour, to study the genomic characteristics of surface attached and agglutinated communities in wastewaters. The representative metagenome assembled genomes of early epiplastic communities and sludge flocs possessed stark differences in metabolic potential, despite community-wide metabolic potential being statistically similar. Early plastic colonizing genera such as Azospira and Uliginosibacterium displayed significantly higher proportions of genes associated with adhesion, chemotaxis, denitrification, and motility, whereas the floc bacteria Microthrix and Mycobacterium harbored polyphosphate, polyhydroxyalkanoate (PHA), and wax accumulation genes, as well as cofactor F420 biosynthesis pathway and sporulation genes for persistence and dispersal. Moreover, these data show that the normalized proportion of virulence factors were highest on plastic surfaces and our metagenomic data suggest that pathogenesis gene sets may facilitate intentional or opportunistic plastic adhesion. Nitrogen metabolism was significantly enriched on plastic when compared with glass surfaces, suggesting plastics may enhance rates of nitrogen cycling. Specifically, Azospira was enriched on PHA and harbored the complete denitrification pathway, underscoring the biotechnological potential of nitrate removal by seeding wastewaters with PHA. Altogether, development of technologies for retaining plastics in wastewaters may prevent inadvertent discharge of putative pathogens and enhance wastewater processing.