New insights in the metabolic behaviour of PAO under negligible poly-P reserves

Acevedo, B.; Murgui, Mónica; Borrás, L.; Barat, R.

doi:10.1016/j.cej.2016.11.073

Cited by 46 publications

(14 citation statements)

References 40 publications

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“…were originally isolated as aromatic compound-degrading bacteria and facultative anaerobic nitrate-reducing bacteria [16,17]. Since then, several Dechloromonas populations have been shown to accumulate poly-P and PHA in situ and/or in axenic cultures [11,13], and several studies have also suggested their potential role as PAOs [18][19][20]. Furthermore, analysis of the Dechloromonas aromatica strain RCB genome revealed the genes required for poly-P accumulation, including polyphosphate kinase, and exopolyphosphatase [21].…”

Section: Introductionmentioning

confidence: 99%

“CandidatusDechloromonas phosphatis” and “CandidatusDechloromonas phosphovora”, two novel polyphosphate accumulating organisms abundant in wastewater treatment systems

Petriglieri

Singleton

Peces

et al. 2020

Preprint

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Members of the genus Dechloromonas are often abundant in enhanced biological phosphorus removal (EBPR) systems and are recognized putative polyphosphate accumulating organisms (PAOs), but their role in phosphate (P) removal is still unclear. Here, we used 16S rRNA gene sequencing and fluorescence in situ hybridization (FISH) to investigate the abundance and distribution of Dechloromonas spp. in Danish wastewater treatment plants. Two species were abundant, novel, and uncultured, and could be targeted by existing FISH probes. Raman microspectroscopy of probe-defined organisms (FISH-Raman) revealed the levels and dynamics of important intracellular storage polymers in abundant Dechloromonas spp. in the activated sludge from four full-scale EBPR plants and from a lab-scale sequencing batch reactor fed with different carbon sources (acetate, glucose, glycine, and glutamate). Moreover, 7 distinct Dechloromonas species were determined from a set of 10 high-quality metagenome-assembled genomes (MAGs) from Danish EBPR plants, each encoding the potential for poly-P, glycogen, and polyhydroxyalkanoates (PHA) accumulation. The two most abundant species exhibited an in situ phenotype in complete accordance with the metabolic information retrieved by the MAGs, with dynamic levels of poly-P, glycogen, and PHA during feast-famine anaerobic-aerobic cycling, legitimately placing these microorganisms among the important PAOs. As no isolates are available for the two species, we propose the names Candidatus Dechloromonas phosphatis and Candidatus Dechloromonas phosphovora.

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Section: Introductionmentioning

confidence: 99%

“CandidatusDechloromonas phosphatis” and “CandidatusDechloromonas phosphovora”, two novel polyphosphate accumulating organisms abundant in wastewater treatment systems

Petriglieri

Singleton

Peces

et al. 2020

Preprint

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“…However, our results revealed that the fraction of PAOs that contain PHV could vary as well with different operational loading conditions, irrelevant to the abundance of GAOs. Acevado et al (2012, 2017) showed that long-time P limited conditions enhance glycolytic pathway to supply energy deficit and shift towards more GAO-like metabolism. It was observed later by da Silva et al (2018) that when polyP is limited, reverse (split) TCA cycle is the most optimal pathway suggesting GAOs are operating reverse TCA cycle.…”

Section: Resultsmentioning

confidence: 99%

Impact of Influent Carbon to Phosphorus Ratio on Performance and Phenotypic Dynamics in Enhanced Biological Phosphorus Removal (EBPR) System - Insights into Carbon Distribution, Intracellular Polymer Stoichiometry and Pathways Shifts

Majed

2019

Preprint

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13This study investigated the impact of influent carbon to phosphorus (P) ratio on the variation in 14 P-removal performance and associated intracellular polymers dynamics in key functionally 15 relevant microbial populations, namely, PAOs and GAOs, at both individual and populations 16 levels, in laboratory scale sequencing batch reactor-EBPR systems. Significant variations and 17 dynamics were evidenced for the formation, utilization and stoichiometry of intracellular 18 polymers, namely polyphosphate, glycogen and Polyhydroxyalkanoates in PAOs and GAOs in 19 the EBPR systems that were operated with influent C/P ranged from 20 to 50, presumably as 20 results of phylogenetic diversity changes and, or metabolic functions shifts in these two 21 populations at different influent C/P ratios. Single cell Raman micro-spectroscopy enabled 22 quantification of differentiated polymer inclusion levels in PAOs and GAOs and, showed that as 23 the influent rbCOD/P ratio increases, the excessive carbon beyond stoichiometric requirement 24 for PAOs would be diverted into GAOs. Our results also evidenced that when condition becomes 25 more P limiting at higher rbCOD/P ratios, both energy and reducing power generation required 26 2 for acetate uptake and PHB formation might shift from relying on both polyP hydrolysis and 1 glycolysis pathway, to more enhancement and dependence on glycolysis in addition to 2 partial/reverse TCA cycle. These findings provided new insights into the metabolic elasticity of 3 PAOs and GAOs and their population-level parameters for mechanistic EBPR modeling. This 4 study also demonstrated the potential of application of single cell Raman micro-spectroscopy 5 method as a powerful tool for studying phenotypic dynamics in ecological systems such as 6 EBPR. 7KEYWORDS Enhanced biological phosphorus removal, EBPR, Raman microscopy, 8 polyphosphate, PHB, glycogen 9 10 phosphorus removal, the benefits are often offset, in practice, by the needs to have standby 1 chemicals for achieving reliable and consistent performance. There is still knowledge gap in 2 understanding the mechanism and factors that control the stability of the process, particularly for 3 achieving extremely low effluent limits and, as a result, process stability and system performance 4 have been seen to vary among facilities (Gu et al., 2005; Neethling et al., 2005; Stephens et al., 5 2004). 6EBPR performance and stability have been shown to be affected by many factors among 7 which, the competition of the two main functionally relevant populations, namely polyphosphate 8 accumulating organisms or PAOs and glycogen accumulating organisms or GAOs, were found 9 to be crucial for achieving successful operation of EBPR. Although deterioration of EBPR 10 performance has been attributed to the proliferation of GAOs in lab-scale EBPRs and also at full 11 scale EBPR facilities (Gu et al., 2005; Cech and Hartman, 1993; Saunders et al., 2003), others 12 (Gu et al., 2008; Tu and Schuler, 2013) have also shown that efficient EBPR could a...

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“…Although the input space was sampled to conform to the assumptions of the metabolic model, i.e., within a narrow range of temperatures, pH and an influent mixture of HAc and HPr, the predictions may not be valid in situations where the PAO population is subject to limiting conditions for extended periods of time. For instance, PAO have been found to shift from PHA to glycogen accumulation in anaerobic conditions following a lack of PO 4 in the influent (Acevedo et al, 2014, 2017)—a phenotypic behavior characteristic of their GAO competitors. Similarly, PAO have been shown to employ the tricarboxylic acid (TCA) cycle to supplement the production of reducing agents to cope with a lack of VFA in the influent, or due to glycogen depletion, possibly as a result of prolonged periods of cellular maintenance (Lanham et al, 2013, 2014).…”

Section: Discussionmentioning

confidence: 99%

Global Sensitivity Analysis of Metabolic Models for Phosphorus Accumulating Organisms in Enhanced Biological Phosphorus Removal

Quang

Rogers

Hofman

et al. 2019

Front. Bioeng. Biotechnol.

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The aim of this study was to identify, quantify and prioritize for the first time the sources of uncertainty in a mechanistic model describing the anaerobic-aerobic metabolism of phosphorus accumulating organisms (PAO) in enhanced biological phosphorus removal (EBPR) systems. These wastewater treatment systems play an important role in preventing eutrophication and metabolic models provide an advanced tool for improving their stability via system design, monitoring and prediction. To this end, a global sensitivity analysis was conducted using standard regression coefficients and Sobol sensitivity indices, taking into account the effect of 39 input parameters on 10 output variables. Input uncertainty was characterized with data in the literature and propagated to the output using the Monte Carlo method. The low degree of linearity between input parameters and model outputs showed that model simplification by linearization can be pursued only in very well defined circumstances. Differences between first and total-order sensitivity indices showed that variance in model predictions was due to interactions between combinations of inputs, as opposed to the direct effect of individual inputs. The major sources of uncertainty affecting the prediction of liquid phase concentrations, as well as intra-cellular glycogen and poly-phosphate was due to 64% of the input parameters. In contrast, the contribution to variance in intra-cellular PHA constituents was uniformly distributed among all inputs. In addition to the intra-cellular biomass constituents, notably PHB, PH2MV and glycogen, uncertainty with respect to input parameters directly related to anaerobic propionate uptake, aerobic poly-phosphate formation, glycogen formation and temperature contributed most to the variance of all model outputs. Based on the distribution of total-order sensitivities, characterization of the influent stream and intra-cellular fractions of PHA can be expected to significantly improve model reliability. The variance of EBPR metabolic model predictions was quantified. The means to account for this variance, with respect to each quantity of interest, given knowledge of the corresponding input uncertainties, was prescribed. On this basis, possible avenues and pre-requisite requirements to simplify EBPR metabolic models for PAO, both structurally via linearization, as well as by reduction of the number of non-influential variables were outlined.

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New insights in the metabolic behaviour of PAO under negligible poly-P reserves

Cited by 46 publications

References 40 publications

“CandidatusDechloromonas phosphatis” and “CandidatusDechloromonas phosphovora”, two novel polyphosphate accumulating organisms abundant in wastewater treatment systems

“CandidatusDechloromonas phosphatis” and “CandidatusDechloromonas phosphovora”, two novel polyphosphate accumulating organisms abundant in wastewater treatment systems

Impact of Influent Carbon to Phosphorus Ratio on Performance and Phenotypic Dynamics in Enhanced Biological Phosphorus Removal (EBPR) System - Insights into Carbon Distribution, Intracellular Polymer Stoichiometry and Pathways Shifts

Global Sensitivity Analysis of Metabolic Models for Phosphorus Accumulating Organisms in Enhanced Biological Phosphorus Removal

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