Ecophysiology of polyphosphate-accumulating organisms and glycogen-accumulating organisms in a continuously aerated enhanced biological phosphorus removal process

Abstract

Aims: To investigate the ecophysiology of populations of polyphosphate‐accumulating organisms (PAO) and glycogen‐accumulating organisms (GAO) in communities of a novel acetate fed process removing phosphate from wastewater. Attempts were made to see if acetate could be replaced by an alternative carbon source which did not support the growth of the GAO. Methods and Results: A continuously aerated sequencing batch reactor was operated with different acetate feed levels. Fluorescence in situ hybridization (FISH) showed that Defluviicoccus GAO numbers increased at lower acetate feed levels. With FISH/microautoradiography (MAR) both detected morphotypes of Defluviicoccus assimilated a wider range of substrates aerobically than Accumulibacter PAO. Their uptake profile differed from that reported for the same phylotype in full scale anaerobic : aerobic EBPR plants. Conclusions: This suggests that replacing acetate with another substrate is unlikely to provide Accumulibacter with a selective advantage in this process. Why Defluviicoccus appeared to out‐compete Accumulibacter at lower acetate concentrations was not clear. Data suggest physiological and morphological diversity may exist within a single Defluviicoccus phylotype. Significance and Impact of the Study: This study implies that the current FISH probes for Defluviicoccus GAO may not reveal the full extent of their biodiversity, and that more information is required before strategies for their control can be devised.

Filamentous members of cluster III Defluviicoccus have the in situ phenotype expected of a glycogen-accumulating organism in activated sludge

“…These observations, combined with their earlier reported ability to accumulate PHA and not polyphosphate (McIlroy & Seviour, 2009; Nittami et al , 2009), support the view that members of both these phylogenetic clusters behave like other Defluviicoccus ‐related organisms (Wong et al , 2004; Meyer et al , 2006; Burow et al , 2007; Wong & Liu, 2007), in having the in situ phenotype expected of GAO. Like other Defluviicoccus ‐related organisms (Wong et al , 2004; Meyer et al , 2006; Ahn et al , 2007; Burow et al , 2007; Wong & Liu, 2007; Schroeder et al , 2008), these FISH‐probed populations possessed a high affinity for the short‐chain fatty acids, acetate and propionate, under both aerobic and anaerobic conditions. None of the other substrates supplied, with the possible exception of glutamate, which was taken up at very low rates, could be utilized under aerobic conditions, which would imply that the Defluviicoccus in activated sludge communities are highly specialized feeders.…”

Research Advances and Challenges in the Microbiology of Enhanced Biological Phosphorus Removal—A Critical Review

“…Other commonly investigated probe-defined organisms exhibiting the GAO phenotype were tetrad-forming organisms, mostly affiliated with a-Proteobacteria, including the Defluviicoccusrelated organisms (Wong et al, 2004). Four clusters of Defluviicoccus-related organisms have been identified McIlroy et al, 2008;Meyer et al, 2006;Wong and Liu, 2007), and the group appears to be phylogenetically diverse and capable of taking up a wide range of substrates under anaerobic-aerobic or aerobic conditions (Burow et al, 2009;Dai et al, 2007;Oehmen et al, 2006;Schroeder et al, 2008). However, their role in EBPR deterioration is uncertain, as they appear to be less abundant in full-scale plants with degraded EBPR capacity (Burow et al, 2007;Wong et al, 2004).…”

Culture-Dependent and -Independent Identification of Polyphosphate-Accumulating <i>Dechloromonas</i> spp. Predominating in a Full-Scale Oxidation Ditch Wastewater Treatment Plant

“…have the ability to store polyP in full-scale WWTPs. In contrast, some research groups reported opposite findings (1, 27, 40); Dechloromonas -related bacteria that dominated in P-removal WWTPs did not accumulate polyP in situ . Furthermore, there have been no studies on the polyP-accumulating abilities of Dechloromonas spp.…”