title: Sodium lauryl ether sulfate (SLES) degradation by nitrate-reducing bacteria.
abstract: The surfactant sodium lauryl ether sulfate (SLES) is widely used in the composition of detergents and frequently ends up in wastewater treatment plants (WWTPs). While aerobic SLES degradation is well studied, little is known about the fate of this compound in anoxic environments, such as denitrification tanks of WWTPs, nor about the bacteria involved in the anoxic biodegradation. Here, we used SLES as sole carbon and energy source, at concentrations ranging from 50 to 1000 mg L-1, to enrich and isolate nitrate-reducing bacteria from activated sludge of a WWTP with the anaerobic-anoxic-oxic (A2/O) concept. In the 50 mg L-1enrichment, Comamonas (50%), Pseudomonas (24%), and Alicycliphilus (12%) were present at higher relative abundance, while Pseudomonas (53%) became dominant in the 1000 mg L-1enrichment. Aeromonas hydrophila strain S7, Pseudomonas stutzeri strain S8, and Pseudomonas nitroreducens strain S11 were isolated from the enriched cultures. Under denitrifying conditions, strains S8 and S11 degraded 500 mg L-1SLES in less than 1 day, while strain S7 required more than 6 days. Strains S8 and S11 also showed a remarkable resistance to SLES, being able to grow and reduce nitrate with SLES concentrations up to 40 g L-1. Strain S11 turned out to be the best anoxic SLES degrader, degrading up to 41% of 500 mg L-1. The comparison between SLES anoxic and oxic degradation by strain S11 revealed differences in SLES cleavage, degradation, and sulfate accumulation; both ester and ether cleavage were probably employed in SLES anoxic degradation by strain S11.
authors.affiliation: Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands. ana.paulo@ceb.uminho.pt.|Department of Chemical Engineering and Environmental Technology, University of Valladolid, Calle Dr. Mergelina s/n, 47011, Valladolid, Spain. ana.paulo@ceb.uminho.pt.|Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal. ana.paulo@ceb.uminho.pt.
authors.forename: Ana M S
authors.initials: AMS
authors.lastname: Paulo
authors.affiliation: Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.|Department of Bioengineering, Adana Science and Technology University, 01180, Seyhan/Adana, Turkey.
authors.forename: Rozelin
authors.initials: R
authors.lastname: Aydin
authors.affiliation: Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.|Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB, Wageningen, The Netherlands.
authors.forename: Mauricio R
authors.initials: MR
authors.lastname: Dimitrov
authors.affiliation: Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
authors.forename: Harm
authors.initials: H
authors.lastname: Vreeling
authors.affiliation: Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal.
authors.forename: Ana J
authors.initials: AJ
authors.lastname: Cavaleiro
authors.affiliation: Department of Chemical Engineering and Environmental Technology, University of Valladolid, Calle Dr. Mergelina s/n, 47011, Valladolid, Spain.
authors.forename: Pedro A
authors.initials: PA
authors.lastname: García-Encina
authors.affiliation: Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.|Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal.
authors.forename: Alfons J M
authors.initials: AJM
authors.lastname: Stams
authors.affiliation: Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Plugge
mesh_terms: D000333:Aeromonas / Q000302:isolation & purification / Q000378:metabolism; D001673:Biodegradation, Environmental; D002244:Carbon / Q000378:metabolism; D042621:Comamonadaceae / Q000302:isolation & purification / Q000378:metabolism; D020585:Comamonas / Q000302:isolation & purification / Q000378:metabolism; D058440:Denitrification; D006090:Gram-Negative Bacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010084:Oxidation-Reduction; D011549:Pseudomonas / Q000302:isolation & purification / Q000378:metabolism; D012722:Sewage / Q000382:microbiology; D012967:Sodium Dodecyl Sulfate / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism
chemical_list: D012722:Sewage; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D002244:Carbon; C408148:sodium laureth sulfate
keywords: Anionic surfactants; Denitrification; Pseudomonas; Sodium lauryl ether sulfate