Meganema perideroedes gen. nov., sp. nov., a filamentous alphaproteobacterium from activated sludge

Abstract

Meganema perideroedes gen. nov., sp. nov., a filamentous alphaproteobacterium from activated sludge An industrial wastewater treatment plant at Grindsted, Denmark, has suffered from bulking problems for several years caused by filamentous bacteria. Five strains were isolated from the sludge by micromanipulation. Phylogenetic analysis of the 16S rRNA gene sequences showed that the strains formed a monophyletic cluster in the Alphaproteobacteria, and they were phenotypically different from their closest relatives and from all hitherto known filamentous bacteria described (closest relative Brevundimonas vesicularis ATCC 11426 T , 89?8 % sequence similarity). In pure culture, the cells (1?5-2?0 mm) in filaments are Gram-negative and contain polyphosphate and polyhydroxyalkanoates. The optimum temperature for growth is 30 6C and the strains grow in 2 % NaCl and are oxidase-and catalase-positive. Ubiquinone 10 is the major quinone. The major fatty acid (C 18 : 1 v7c) and smaller amounts of unsaturated fatty acids, 3-hydroxy fatty acids with a chain length of 16 and 18 carbon atoms and small amounts of 10-methyl-branched fatty acids with 18 carbon atoms (C 19 : 0 10-methyl) affiliated the strains with the Methylobacterium/Xanthobacter group in the Alphaproteobacteria. The G+C content of the DNA is 42?9 mol% (for strain Gr1 T ).The two most dissimilar isolates by 16S rRNA gene comparison (Gr1 T and Gr10; 97?7 % identical)showed 71?5 % DNA-DNA relatedness. Oligonucleotide probes specific for the pure cultures were designed for fluorescence in situ hybridization and demonstrated that two filamentous morphotypes were present in the Grindsted wastewater treatment plant. It is proposed that the isolates represent a new genus and species, Meganema perideroedes gen. nov., sp. nov. The type strain of Meganema perideroedes is strain Gr1 T (=DSM 15528Filamentous bacteria affiliated to the Alphaproteobacteria were isolated from activated sludge biomass from a wastewater treatment plant (WWTP) in Grindsted, Denmark. The treatment plant has carbon removal, the mean cell residence time (sludge age) is 8-10 days, the annual mean temperature is 15-25 u C and the salinity is relatively high, with a conductivity between 15 and 23 mS cm 21 and a sodium concentration around 5-7 g l 21. The plant has been affected by bulking problems for several years, mainly caused by Thiothrix spp. (Nielsen et al., 2000) and other bacteria similar to the isolates reported in this study. Five strains (Gr1 T , Gr2, Gr5, Gr10 and Gr28) were isolated by micromanipulation using a Skerman micromanipulator as described by Blackall (1991) and grown on R2A agar medium (Reasoner & Geldreich, 1985). Gliding motility, Gram-and Neisser-staining (for Gram-reaction and polyphosphate inclusions, respectively; Eikelboom & van Buijsen, 1983) and poly-b-hydroxybutyrate (PHB) inclusions as visualized by Nile blue staining (Ostle & Holt, 1982) were investigated. Only Gr1 T and Gr10 were characterized phenotypically, but they were not able to grow on minimal media (Williams & ...

Ecophysiology of different filamentous Alphaproteobacteria in industrial wastewater treatment plants

“…The filamentous Alphaproteobacteria have been observed and described in several studies in the past 4 years (Dionisi et al, 2002;Levantesi et al, 2004;Thomsen et al, 2006;van der Waarde et al, 2002) and, based on 16S rRNA gene sequences from six uncultured bacteria and one isolated species, they have now been described as constituting seven distantly related phylogenetic clusters: 'Candidatus Combothrix italica', 'Candidatus Catenimonas italica', 'Candidatus Sphaeronema italicum', 'Candidatus Alysiosphaera europaea', 'Candidatus Monilibacter batavus', 'Candidatus Alysiomicrobium bavaricum' (Levantesi et al, 2004) and Meganema perideroedes (Thomsen et al, 2006). Oligonucleotide probes for detection of these species by FISH are also available (Levantesi et al, 2004;Thomsen et al, 2006).…”

“…Such knowledge is of major importance for developing efficient control strategies. At present only isolates of Meganema perideroedes exist in pure culture (Levantesi et al, 2004;Thomsen et al, 2006), but isolates of 'Ca. Alysiosphaera europaea' coexisting with a yeast (Debaryomyces hansenii) are available .…”

“…Alysiosphaera europaea' coexisting with a yeast (Debaryomyces hansenii) are available . The physiological properties of Meganema perideroedes have been examined in pure culture (Levantesi et al, 2004;Thomsen et al, 2006) and data on the ecophysiology of Meganema perideroedes have been obtained (Kragelund et al, 2005). This filamentous bacterium is a very versatile consumer of a variety of organic substrates under aerobic conditions and it has a very large storage capacity, measured as polyhydroxyalkanoates (PHAs) formed from different substrates in the presence of different electron acceptors (e-acceptors).…”

The effect of malathion on the activity, performance, and microbial ecology of activated sludge

“…6). Several bacterial groups exhibited a decline in relative abundance after exposure to 3 mg/L of malathion including: Meganema, a well-known filamentous organism (Thomsen et al, 2006); lactic acid bacteria, namely: Leucobacter, Lactococcus, Leuconostoc (ASM Press, 2007), Crocinitomix; and Bdellovibrio, a gram-negative, rodshaped aerobic strain suspected of preying on other gram-negative bacteria (Davidov and Jurkevitch, 2004). Meganema and Leucobacter also declined in the control reactor (data not shown), indicating that malathion may not have affected these two groups in reactor II.…”

Filamentous Bacterium Eikelboom Type 0092 in Activated Sludge Plants in Australia Is a Member of the Phylum Chloroflexi

“…Hence, they are often still referred to as numerical types persisting from the study of Eikelboom (18). Success has been achieved with some cultured and uncultured filaments in elucidating their phylogeny from 16S rRNA sequence analyses (6,9,10,31,50) and providing them with valid names (37,49). Furthermore, with such sequence information, rRNA targeted oligonucleotide probes have been designed for their in situ identification and, together with microautoradiography (MAR) and other techniques (29,40), their ecophysiology may be elucidated (25,27,28).…”