Characterization of the In Situ Ecophysiology of Novel Phylotypes in Nutrient Removal Activated Sludge Treatment Plants.

Simon Jon McIlroy,Mads Albertsen,Marta Nierychlo,Tomonori Kindaichi,Takanori Awata,Per Halkjær Nielsen,Nicole Webster

doi:10.1371/journal.pone.0136424

Simon Jon McIlroy, Mads Albertsen + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0136424

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Abstract

An in depth understanding of the ecology of activated sludge nutrient removal wastewater treatment systems requires detailed knowledge of the community composition and metabolic activities of individual members. Recent 16S rRNA gene amplicon surveys of activated sludge wastewater treatment plants with nutrient removal indicate the presence of a core set of bacterial genera. These organisms are likely responsible for the bulk of nutrient transformations underpinning the functions of these plants. While the basic activities of some of these genera in situ are known, there is little to no information for the majority. This study applied microautoradiography coupled with fluorescence in situ hybridization (MAR-FISH) for the in situ characterization of selected genus-level-phylotypes for which limited physiological information is available. These included Sulfuritalea and A21b, both within the class Betaproteobacteria, as well as Kaga01, within sub-group 10 of the phylum Acidobacteria. While the Sulfuritalea spp. were observed to be metabolically versatile, the A21b and Kaga01 phylotypes appeared to be highly specialized.

Highlights

Wastewater treatment using activated sludge represents one of the largest biotechnology industries in the world
Phylogenetic placement of representative 16S rRNA gene sequences and the design of Fluorescence in situ hybridization (FISH) probes for selected groups were performed with the ARB software package [10]
This study applied MAR-FISH for the preliminary characterization of the in situ behaviour of three phylotypes suggested as abundant members of the activated sludge community

Summary

Introduction

Wastewater treatment using activated sludge represents one of the largest biotechnology industries in the world These systems employ a diverse consortium of microbes primarily for the removal of carbon, nitrogen and phosphorus from wastewater streams. Removal of such nutrients is important for the prevention of the eutrophication of aquatic ecosystems receiving the treated water [1]. An in depth understanding of the ecology of these biotechnological systems is key for their optimal design and efficient operation [2] Important to this goal will be the characterization of the individual contribution of each bacterial genus-level-taxon to system function [3]. An amplicon-sequencing based survey of 13 Danish full-scale plants with nutrient removal observed that a relatively small

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