Metagenomic analysis of an ecological wastewater treatment plant’s microbial communities and their potential to metabolize pharmaceuticals

Abstract

Pharmaceuticals and other micropollutants have been detected in drinking water, groundwater, surface water, and soil around the world. Even in locations where wastewater treatment is required, they can be found in drinking water wells, municipal water supplies, and agricultural soils. It is clear conventional wastewater treatment technologies are not meeting the challenge of the mounting pressures on global freshwater supplies. Cost-effective ecological wastewater treatment technologies have been developed in response. To determine whether the removal of micropollutants in ecological wastewater treatment plants (WWTPs) is promoted by the plant-microbe interactions, as has been reported for other recalcitrant xenobiotics, biofilm microbial communities growing on the surfaces of plant roots were profiled by whole metagenome sequencing and compared to the microbial communities residing in the wastewater. In this study, the concentrations of pharmaceuticals and personal care products (PPCPs) were quantified in each treatment tank of the ecological WWTP treating human wastewater at a highway rest stop and visitor center in Vermont. The concentrations of detected PPCPs were substantially greater than values reported for conventional WWTPs likely due to onsite recirculation of wastewater. The greatest reductions in PPCPs concentrations were observed in the anoxic treatment tank where Bacilli dominated the biofilm community. Benzoate degradation was the most abundant xenobiotic metabolic category identified throughout the system. Collectively, the microbial communities residing in the wastewater were taxonomically and metabolically more diverse than the immersed plant root biofilm. However, greater heterogeneity and higher relative abundances of xenobiotic metabolism genes was observed for the root biofilm.

Implementation of Omics Research to Enhance Phytoremediation Efficiency - a Review

“…During one research, metagenomic sequencing of plasmid DNA from municipal wastewater-treatment plants displayed, that genes involved in heavy metal resistance are disproportionately abundant in plasmid DNA in comparison to the entire genome. The same study showed, that genes involved in the transformation and degradation of organic pollutants are also mostly present in plasmids [24]. Such knowledge has already been applied, and plasmids with genes responsible for toluene degradation were successfully transferred to aerial plant endophytes and increased the total degradation of contaminant that would have been volatilized [26].…”

“…Introduction of plants to highly degraded and contaminated soils may augment both the quantity and quality of microbial populations occurring in bulk soil [24]. Although plant-microbe interactions are incredibly complex and sensitive to different environmental conditions, plants can favour certain species that promote its growth or inhibit the activity of pathogens.…”

“…Also, the analysis of metagenomic DNA showed specific taxa which are involved in the suppression of plants diseases in soils [21]. Experiments by Balcom et al displayed the potential of microorganisms to metabolise micropollutants such as xenobiotics during the process of wastewater treatment [24]. Metagenomic analysis revealed microorganisms and specific genes involved in degradation of benzoate.…”

Assessing the performance of different approaches for functional and taxonomic annotation of metagenomes

“…Because of these problems, some authors prefer to skip the assembly step and proceed to the direct functional/taxonomic annotation of the raw reads, especially when the aim is to obtain a functional or taxonomic profile of the metagenome [3][4][5][6][7][8].…”

Tools for Metagenomic Analysis at Wastewater Treatment Plants: Application to a Foaming Episode

“…Workers have also studied antibiotic-resistant genes in WWTP reactors (Christgen et al, 2015), and their mobility among organisms within plants (Munck et al, 2015;Wang, et al, 2013). Other works are illuminating capacities to decompose pharmaceuticals (Balcom et al, 2016) and phenol (Silva et al, 2012) in wastewaters. And another has identified possible biological mechanisms contributing to concrete corrosion (Gomez-Alvarez et al, 2012).…”