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

Abstract

The in situ ecophysiology of alphaproteobacterial filamentous Cluster III Defluviicoccus present in enhanced biological phosphorus removal (EBPR)-activated sludge systems was evaluated using FISH-MAR and histochemical staining methods. These organisms, sharing the Nostocoida limicola morphotype, are known to be responsible for serious episodes of activated sludge bulking. The data presented here also demonstrate an ability to assimilate short-chain fatty acids and synthesize poly-β-hydroxyalkanoates (PHA) anaerobically, and then utilize this stored PHA under aerobic conditions, but with no corresponding synthesis of polyphosphate. These features are consistent with an in situ phenotype of glycogen-accumulating organisms (GAO), populations thought to lower the efficiency of EBPR systems by outcompeting polyphosphate-accumulating organisms (PAO) for substrates in their anaerobic feed phase. Survey data indicate that these GAO are as commonly seen as the known PAO in full-scale EBPR-activated sludge systems, which suggest that they might play important roles there, and therefore should not be viewed just as laboratory curiosities.

A Critical Assessment of the Microorganisms Proposed to be Important to Enhanced Biological Phosphorus Removal in Full-Scale Wastewater Treatment Systems

“…GAO phenotype has also been demonstrated for the sole isolate, D. vanus , a member of cluster 1 (Maszenan et al, 2005; Wong and Liu, 2007). Anaerobic carbon storage as PHA has also been shown in situ for clusters 3 and 4 (McIlroy et al, 2010). In this study, OTUs representing clusters 2 and 3 made up the majority (>90%) of amplicon reads assigned to the genus, which is consistent with FISH analyses of full-scale systems ( Figure 8 ; Burow et al, 2007; McIlroy and Seviour, 2009).…”

“…The application of molecular methods has also allowed the study of the putative GAO in situ where the phenotype has been at least partially confirmed for: the actinobacterial genus Micropruina and closely related sbr-gs28 taxon (Kong et al, 2001), the gammaproteobacterial family Competibacteraceae (Kong et al, 2006) and CCM19a phylotype (probe Gam445) (Kong et al, 2007), the alphaproteobacterial genus Defluviicoccus (Wong et al, 2004; Meyer et al, 2006; Burow et al, 2007; Wong and Liu, 2007; McIlroy et al, 2010), and the betaproteobacterial genera Propionivibrio (Albertsen et al, 2016), and Spb280 (probe Bet65; Kong et al, 2007). …”

Metagenomic characterization of ‘Candidatus Defluviicoccus tetraformis strain TFO71’, a tetrad‐forming organism, predominant in an anaerobic–aerobic membrane bioreactor with deteriorated biological phosphorus removal

“…Two types of GAO are often observed in full and laboratory-scale EBPR systems: 'Candidatus Competibacter phosphatis' of the class Gammaproteobacteria (Crocetti et al, 2002;Kong et al, 2002) and Defluviicoccus-related GAO of the Rhodospirillaceae family in the class Alphaproteobacteria (Wong et al, 2004;Wong and Liu, 2006;McIlroy and Seviour, 2009;Mielczarek et al, 2013). For the Defluviicoccus-related GAO, tetrad-forming (DTFO) (cluster I, II and IV) and filamentous clades (cluster III) have been characterized EBPR systems as potential PAO competitors (Wong et al, 2004;Burow et al, 2007;Wong and Liu, 2007;McIlroy and Seviour, 2009;McIlroy et al, 2010). These clusters have varying predominance in full and laboratoryscale EBPR systems; for example, cluster I and III prevalence is associated with laboratory and full-scale systems respectively, while cluster II have been observed to predominate in both systems (Wong et al, 2004;Burow et al, 2007;Nittami et al, 2009).…”

From macro to lab-scale: Changes in bacterial community led to deterioration of EBPR in lab reactor

“…When culture-independent techniques were implemented, it was found that large coccobacillus-shaped Candidatus Competibacter phosphatis [9,10] in the Gammaproteobacteria (hereafter referred to as Competibacter or GB-GAO), and Defluviicoccus-related species (Dv-GAO) in the Alphaproteobacteria [11,12], are the most frequently reported GAOs in both lab-scale and full-scale deteriorated EBPR reactors. There is a distinct differentiation within the GAOs; GB-GAOs are composed of at least seven sub-groups [9], while DvGAOs comprise four clusters [13,14].…”