BIOREFINE Project – Screening of phosphate accumulating organisms
in samples of activated sludge taken from wastewater treatment plants
At this time, many wastes are used or eliminated through processes that do not really consider their potential applications. Such wastes contain useful nutrients (nitrogen, phosphorus and potassium) which are widely used in agriculture as fertilisers. More specifically, wastewater contains low phosphate concentrations. These concentrations considerably increase during wastewater treatment in wastewater treatment plants. Indeed, phosphate is concentrated in sewage sludge through chemical and/or biological treatment(s). Another important observation is the presence of specific bacteria which are able to accumulate phosphorus in wastewater treatment plants. These microorganisms, called “Phosphate Accumulating Organisms” (PAOs), can store phosphorus under the form of linear polymers of polyphosphate. Here, our aim was to study the microbiotas in four samples of activated sludge and to point out the presence of PAOs, which was confirmed by a metagenetic analysis. Enriched cultures were obtained from the different samples, and the metabolic activities of these artificial consortia were determined. Several bacterial strains were isolated from the samples and their potential ability to accumulate phosphorus was investigated. The positive strains were found to belong to the genera Pseudomonas, Acinetobacter and Corynebacterium. Finally, electron microscopy confirmed the presence of polyphosphate granules inside the cells. This work is supported by the BioRefine Project, a European project in which several member states focus on recovery of inorganics from organic waste streams. We gratefully acknowledge the INTERREG IVB NWE programme, through the BioRefine research grant (ref. 320J-BIOREFINE).
Introduction
The biological phosphate removal from wastewater is achieved by a specific microflora in WWTPs
Sampling of activated sludge in 3 WWTPs achieving a 100% biological phosphate removal
Tarayre C1, Charlier R1, Michels E2, Meers E2, Delvigne F1
1 - MiPI - Gembloux Agro-Bio Tech, University of Liege, Belgium 2 - Faculty of Bioscience Engineering, Ghent University, Belgium
This work is supported by the BioRefine Project (INTERREG IVB NWE
Programme) (ref. 320J-BIOREFINE)
In Wallonia, there are only 3 WWTPs which achieve phosphate removal through a 100% biological pathway!
WWTP2 (L) WWTP3 (M) WWTP4 (C) (NC) . . . . . . . . . . . . Analyses
The partners of the BioRefine Project
Acknowledgements Results
Anaerobic conditions Aerobic-anoxic conditions
CH3COOH Polyhydroxy-butyrate Glycogen NADH2 Poly-phosphate ATP PO43- Polyhydroxy-butyrate Glycogen GROWTH Poly-phosphate ATP NADH2 PO43- O2 NO3- H2O or N2 PO43- PO43- PO43- WWTP1 (B) Enrichment of consortia Analysis of consortia through metagenomics Metabolic analysis of enriched consortia Isolation of PAOs
Metagenetic analysis (OTUs) Isolation of PAOs
Metabolic activities
Strong effect of enrichment on consortia
Polyphosphate detection by STEM
* Raw samples
C (NC) B L M
* Enrichment in minimal acetate medium
C (NC) B L M
* Isolation of potential PAOs on solid MAM
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* Screening of PAOs on XPi medium
Solid medium with PO43-
and XPi Solid medium with XPi only
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Positive PAOs identified as Pseudomonas sp.,
Corynebacterium sp. and Acinetobacter sp. PP
