title: Filamentous Alphaproteobacteria associated with bulking in industrial wastewater treatment plants.
abstract: The phylogeny and distribution of filamentous Alphaproteobacteria, morphologically similar to "Nostocoida limicola" and Eikelboom Type 021N that cause the solids separation problem of bulking in industrial activated sludge plants is described here. A combination of culture-dependent and culture-independent molecular methods has characterized 5 novel species. 16S rRNA targeted oligonucleotide probes were designed for their in situ identification by fluorescence in situ hybridisation (FISH) and used to monitor their presence in 86 WWTPs treating different industrial effluents in four European countries. The involvement of these bacteria in bulking in these plants was confirmed. Filaments hybridising with the ALF-968 probe for the Alphaproteobacteria were present in 65% of the WWTPs examined. They were dominant and therefore probably responsible for bulking in 25.5% of them. The heterogeneous filamentous alphaproteobacterial populations in these communities could be completely identified after application of the oligonucleotide probes used in this study in 91% of the plants containing them. The only filamentous Alphaproteobacteria retrieved in pure culture was isolated from three different industrial WWTPs plants. None of these isolates could grow anaerobically on glucose or denitrify, but all grew aerobically and heterotrophically on a range of carbon sources. Although morphologically similar to the Eikelboom Type 021N morphotype, they were not involved in sulphur metabolism. These bacteria accumulated lipidic storage granules that were associated with their presence under the unbalanced growth conditions existing in these plants.
authors.affiliation: CNR, Water Research Institute, Rome, Italy. levantesi@irsa.rm.cnr.it
authors.forename: Caterina
authors.initials: C
authors.lastname: Levantesi
authors.forename: Claudia
authors.initials: C
authors.lastname: Beimfohr
authors.forename: Bert
authors.initials: B
authors.lastname: Geurkink
authors.forename: Simona
authors.initials: S
authors.lastname: Rossetti
authors.forename: Karin
authors.initials: K
authors.lastname: Thelen
authors.forename: Janneke
authors.initials: J
authors.lastname: Krooneman
authors.forename: Jiri
authors.initials: J
authors.lastname: Snaidr
authors.forename: Jaap
authors.initials: J
authors.lastname: van der Waarde
authors.forename: Valter
authors.initials: V
authors.lastname: Tandoi
mesh_terms: D000332:Aerobiosis; D020561:Alphaproteobacteria / Q000145:classification* / Q000166:cytology / Q000302:isolation & purification* / Q000502:physiology; D000693:Anaerobiosis; D050260:Carbohydrate Metabolism; D003594:Cytoplasmic Granules; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000737:chemistry / Q000302:isolation & purification; D005060:Europe; D020459:Genes, rRNA / Q000235:genetics; D017403:In Situ Hybridization; D050356:Lipid Metabolism; D008853:Microscopy; D008969:Molecular Sequence Data; D017672:Nitrogen Compounds / Q000378:metabolism; D010802:Phylogeny; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000032:analysis / Q000235:genetics; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D013457:Sulfur Compounds / Q000378:metabolism; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D017672:Nitrogen Compounds; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D013457:Sulfur Compounds