Eukaryotic molecular diversity at different steps of the wastewater treatment plant process reveals more phylogenetic novel lineages

Abstract

Wastewater microbiota represents important actors of organic depollution. Nowadays, some species used as bioindicators of the effluent quality are still identified by microscopy. In the present study, we investigated eukaryotic diversity at the different steps of the treatment process of a wastewater treatment plant (aerobic, anaerobic, clarifier basins and anaerobic digester) using the 18S rRNA gene sequencing approach. Of the 1519 analysed sequences, we identified 160 operational taxonomic units. Interestingly, 56.9% of the phylotypes were assigned to novel phylogenetic molecular species since they show <97% sequence identity with their nearest affiliated representative within public databases. Peritrichia ciliates were the most predominant group, with Epistylis as the most common genus. Although anaerobic, the digester appears to harbor many unclassified phylotypes of protozoa species. Novel lineages such as LKM11 and LKM118 were widely represented in the digester. Diversity values given by Shannon indexes show that the clarifier is the most diversified. This work will help designing molecular tools that are fast, reliable, and reproducible for monitoring wastewater depollution and studying phylogenetic relationships among the wonderful world of protists within this anthropogenic ecosystem.

Fungi in aquatic ecosystems

“…99 ). A multitude of recent studies confirmed next to fermentative yeasts a dominance of "dark matter fungi" (mainly Rozellomycota), often in the anaerobic, biofilm dominated stages [100][101][102][103][104] . Their function in wastewater processing is unclear, and it will be highly interesting, if "dark matter fungi" have the same potential for biotechnologies than higher fungi (e.g.…”

Acetate promotes microbial reductive debromination of tetrabromobisphenol A during the startup phase of anaerobic wastewater sludge bioreactors

“…Species within the Parcubacteria appear to be obligate anaerobe and likely live in symbiosis with a wide range of other prokaryotic or eukaryotic members of the community (Nelson and Stegen, 2015). Particularly, one taxon was observed as an endoplasmic symbiont of a freeliving Ciliophora (Gong et al, 2014), which can represent a dominant fraction of the eukaryotic microbial community in WWTPs (Chouari et al, 2017;Matsunaga et al, 2014). The detection of positive-responder OTUs related to protozoan-associated bacteria could indicate that symbiotic associations within wastewater systems might be much more prevalent than currently thought, and that the presence of TBBPA might stimulate the establishment of such symbiotic relationships within the community.…”

Specificity of RNA folding and its association with evolutionarily adaptive mRNA secondary structure

“…To this end, we borrowed the idea of Shannon's metric of information entropy (Shannon 2001) (Shannon index), which quantifies the uncertainty in predicting the identity of a randomly chosen entity from a system. Shannon index is frequently used in ecology as an index for species diversity (the uncertainty of predicting the species randomly captured from a community) (Tuomisto 2010), or similarly for measuring molecular diversity in various biological systems (the uncertainty of predicting the sequence randomly picked from a pool of nucleic acid or protein) (Lin 1996;Medinger, et al 2010;Chouari, et al 2017;Mangin, et al 2017), or RNA folding specificity as defined by the computationally predicted ensemble of secondary structures (Huynen, et al 1997). Adapted from Shannon entropy, we measured the diversity of folding by obs = − ∑ , , ln , .…”