title: Bacterial community shifts in nonylphenol polyethoxylates-enriched activated sludge.
abstract: A molecular approach was used to evaluate the effect of nonylphenol ethoxylate surfactants on the bacterial diversity in lab-scale activated sludge reactors. Separate bench-scale units were fed synthetic wastewater with and without addition of branched nonylphenol ethoxylates (NPnEO). The performance of the reactors, in terms of carbonaceous removal was largely unaffected by the presence of NP10EO in the feeding solution. However, addition of NP10EO exerted a pronounced shift in bacterial community composition. In situ hybridization analyzing larger phylogenetic groups of bacteria with ribosomal RNA-targeted oligonucleotide probes revealed the dominance of clusters composed of Betaproteobacteria, accounting for up to one-third of 4',6-diamidino-2-phenylindol-dihydrochloride (DAPI)-stained cells in NP10EO amended reactors and only 5% of DAPI-stained cells in the controls. These shifts in populations of larger phylogenetic groups were confirmed by dot-blot analysis of rRNA. Members of gamma subclass of Proteobacteria were present in low numbers in all activated sludge samples examined, suggesting that only bacteria affiliated with the beta subclass of Proteobacteria may have a specific role in NP10EO degradation.
authors.affiliation: Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Vuelta de Obligado 2490, 1428 Buenos Aires, Argentina.
authors.forename: Mariana
authors.initials: M
authors.lastname: Lozada
authors.forename: R F Raúl F
authors.initials: RF
authors.lastname: Itria
authors.forename: E L M Eva L M
authors.initials: EL
authors.lastname: Figuerola
authors.forename: P A Paola A
authors.initials: PA
authors.lastname: Babay
authors.forename: R T Raquel T
authors.initials: RT
authors.lastname: Gettar
authors.forename: L A Luis A
authors.initials: LA
authors.lastname: de Tullio
authors.forename: Leonardo
authors.initials: L
authors.lastname: Erijman
mesh_terms: D000332:Aerobiosis; D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D020562:Betaproteobacteria / Q000145:classification / Q000235:genetics; D001673:Biodegradation, Environmental; D005026:Ethylene Glycols / Q000737:chemistry*; D005399:Fishes; D005456:Fluorescent Dyes; D020563:Gammaproteobacteria / Q000145:classification / Q000235:genetics; D017403:In Situ Hybridization; D015345:Oligonucleotide Probes / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D012722:Sewage / Q000032:analysis / Q000382:microbiology*; D012988:Soil Microbiology; D013501:Surface-Active Agents / Q000737:chemistry; D013997:Time Factors
chemical_list: D005026:Ethylene Glycols; D005456:Fluorescent Dyes; D015345:Oligonucleotide Probes; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D013501:Surface-Active Agents; C021754:terics