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Metaproteomics provides functional insight into activated sludge wastewater treatment.

Wilmes P, Wexler M, Bond PL - PLoS ONE (2008)

Bottom Line: A laboratory-scale sequencing batch reactor was successfully operated for different levels of EBPR, removing around 25, 40 and 55 mg/l P.Several proteins involved in cellular stress response were detected.Finally, the results are discussed in relation to current EBPR metabolic models.

View Article: PubMed Central - PubMed

Affiliation: School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom.

ABSTRACT

Background: Through identification of highly expressed proteins from a mixed culture activated sludge system this study provides functional evidence of microbial transformations important for enhanced biological phosphorus removal (EBPR).

Methodology/principal findings: A laboratory-scale sequencing batch reactor was successfully operated for different levels of EBPR, removing around 25, 40 and 55 mg/l P. The microbial communities were dominated by the uncultured polyphosphate-accumulating organism "Candidatus Accumulibacter phosphatis". When EBPR failed, the sludge was dominated by tetrad-forming alpha-Proteobacteria. Representative and reproducible 2D gel protein separations were obtained for all sludge samples. 638 protein spots were matched across gels generated from the phosphate removing sludges. 111 of these were excised and 46 proteins were identified using recently available sludge metagenomic sequences. Many of these closely match proteins from "Candidatus Accumulibacter phosphatis" and could be directly linked to the EBPR process. They included enzymes involved in energy generation, polyhydroxyalkanoate synthesis, glycolysis, gluconeogenesis, glycogen synthesis, glyoxylate/TCA cycle, fatty acid beta oxidation, fatty acid synthesis and phosphate transport. Several proteins involved in cellular stress response were detected.

Conclusions/significance: Importantly, this study provides direct evidence linking the metabolic activities of "Accumulibacter" to the chemical transformations observed in EBPR. Finally, the results are discussed in relation to current EBPR metabolic models.

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Related in: MedlinePlus

Master 2D-PAGE gel of the EBPR matchset with excised protein spots highlighted.Spot numbering corresponds to the numbering used in Table 2, and supporting information Table S3.
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pone-0001778-g003: Master 2D-PAGE gel of the EBPR matchset with excised protein spots highlighted.Spot numbering corresponds to the numbering used in Table 2, and supporting information Table S3.

Mentions: For each P increase level, 2D-PAGE separations of the proteins extracted from the four distinct sludges were carried out (Fig. 2), and from the gel separations metaproteomic maps were generated. Liquid isoelectric focussing prior to 2D-PAGE was employed to improve the gel separations. For each sludge highly reproducible metaproteomic maps were obtained, with >98 % of protein spots being matched within replicate gels (n = 3; Table S2). Additionally, the proteomic maps generated from the EBPR28, EBPR42 and EBPR55 sludges exhibited high similarity. Overall, a total of 638 spots were matched between all the gels for the EBPR sludges, and these conserved spots are represented on the “Master” gel (Fig. 3). The proteomic maps produced from nEBPR70 sludge samples were distinct compared to those generated from the EBPR sludges, and were analysed separately.


Metaproteomics provides functional insight into activated sludge wastewater treatment.

Wilmes P, Wexler M, Bond PL - PLoS ONE (2008)

Master 2D-PAGE gel of the EBPR matchset with excised protein spots highlighted.Spot numbering corresponds to the numbering used in Table 2, and supporting information Table S3.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2289847&req=5

pone-0001778-g003: Master 2D-PAGE gel of the EBPR matchset with excised protein spots highlighted.Spot numbering corresponds to the numbering used in Table 2, and supporting information Table S3.
Mentions: For each P increase level, 2D-PAGE separations of the proteins extracted from the four distinct sludges were carried out (Fig. 2), and from the gel separations metaproteomic maps were generated. Liquid isoelectric focussing prior to 2D-PAGE was employed to improve the gel separations. For each sludge highly reproducible metaproteomic maps were obtained, with >98 % of protein spots being matched within replicate gels (n = 3; Table S2). Additionally, the proteomic maps generated from the EBPR28, EBPR42 and EBPR55 sludges exhibited high similarity. Overall, a total of 638 spots were matched between all the gels for the EBPR sludges, and these conserved spots are represented on the “Master” gel (Fig. 3). The proteomic maps produced from nEBPR70 sludge samples were distinct compared to those generated from the EBPR sludges, and were analysed separately.

Bottom Line: A laboratory-scale sequencing batch reactor was successfully operated for different levels of EBPR, removing around 25, 40 and 55 mg/l P.Several proteins involved in cellular stress response were detected.Finally, the results are discussed in relation to current EBPR metabolic models.

View Article: PubMed Central - PubMed

Affiliation: School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom.

ABSTRACT

Background: Through identification of highly expressed proteins from a mixed culture activated sludge system this study provides functional evidence of microbial transformations important for enhanced biological phosphorus removal (EBPR).

Methodology/principal findings: A laboratory-scale sequencing batch reactor was successfully operated for different levels of EBPR, removing around 25, 40 and 55 mg/l P. The microbial communities were dominated by the uncultured polyphosphate-accumulating organism "Candidatus Accumulibacter phosphatis". When EBPR failed, the sludge was dominated by tetrad-forming alpha-Proteobacteria. Representative and reproducible 2D gel protein separations were obtained for all sludge samples. 638 protein spots were matched across gels generated from the phosphate removing sludges. 111 of these were excised and 46 proteins were identified using recently available sludge metagenomic sequences. Many of these closely match proteins from "Candidatus Accumulibacter phosphatis" and could be directly linked to the EBPR process. They included enzymes involved in energy generation, polyhydroxyalkanoate synthesis, glycolysis, gluconeogenesis, glycogen synthesis, glyoxylate/TCA cycle, fatty acid beta oxidation, fatty acid synthesis and phosphate transport. Several proteins involved in cellular stress response were detected.

Conclusions/significance: Importantly, this study provides direct evidence linking the metabolic activities of "Accumulibacter" to the chemical transformations observed in EBPR. Finally, the results are discussed in relation to current EBPR metabolic models.

Show MeSH
Related in: MedlinePlus