title: Impact of biogenic substrates on sulfamethoxazole biodegradation kinetics by Achromobacter denitrificans strain PR1.
abstract: Pure cultures have been found to degrade pharmaceutical compounds. However, these cultures are rarely characterized kinetically at environmentally relevant concentrations. This study investigated the kinetics of sulfamethoxazole (SMX) degradation by Achromobacter denitrificans strain PR1 at a wide range of concentrations, from ng/L to mg/L, to assess the feasibility of using it for bioaugmentation purposes. Complete removal of SMX occurred for all concentrations tested, i.e., 150 mg/L, 500 µg/L, 20 µg/L, and 600 ng/L. The reaction rate coefficients (kbio) for the strain at the ng/L SMX range were: 63.4 ± 8.6, 570.1 ± 15.1 and 414.9 ± 124.2 L/g[Formula: see text]·day), for tests fed without a supplemental carbon source, with acetate, and with succinate, respectively. These results were significantly higher than the value reported for non-augmented activated sludge (0.41 L/(g [Formula: see text]·day) with hundreds of ng/L of SMX. The simultaneous consumption of an additional carbon source and SMX suggested that the energetic efficiency of the cells, boosted by the presence of biogenic substrates, was important in increasing the SMX degradation rate. The accumulation of 3-amino-5-methylisoxazole was observed as the only metabolite, which was found to be non-toxic. SMX inhibited the Vibrio fischeri luminescence after 5 min of contact, with EC50values of about 53 mg/L. However, this study suggested that the strain PR1 still can degrade SMX up to 150 mg/L. The results of this work demonstrated that SMX degradation kinetics by A. denitrificans PR1 compares favorably with activated sludge and the strain is a potentially interesting organism for bioaugmentation for SMX removal from polluted waters.
authors.affiliation: UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, 2829-516, Lisbon, Portugal.
authors.forename: P Y
authors.initials: PY
authors.lastname: Nguyen
authors.affiliation: UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, 2829-516, Lisbon, Portugal. gs.carvalho@fct.unl.pt.
authors.forename: Gilda
authors.identifier: 0000-0002-3514-806X
authors.initials: G
authors.lastname: Carvalho
authors.affiliation: LEPABE-Chemical Engineering Department, Faculty of Engineering, University of Porto, 4200-465, Porto, Portugal.
authors.forename: A C
authors.initials: AC
authors.lastname: Reis
authors.affiliation: LEPABE-Chemical Engineering Department, Faculty of Engineering, University of Porto, 4200-465, Porto, Portugal.
authors.forename: O C
authors.initials: OC
authors.lastname: Nunes
authors.affiliation: UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, 2829-516, Lisbon, Portugal.
authors.forename: M A M
authors.initials: MAM
authors.lastname: Reis
authors.affiliation: UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, 2829-516, Lisbon, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Oehmen
mesh_terms: D042441:Achromobacter denitrificans / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental / Q000187:drug effects; D018533:Biomass; D002244:Carbon / Q000378:metabolism; D007700:Kinetics; D055442:Metabolome / Q000187:drug effects; D008954:Models, Biological; D013379:Substrate Specificity / Q000187:drug effects; D013420:Sulfamethoxazole / Q000378:metabolism* / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000378:metabolism
chemical_list: D014874:Water Pollutants, Chemical; D002244:Carbon; D013420:Sulfamethoxazole
keywords: Antibiotics; Bioaugmentation; Co-metabolism; Ecotoxicity; Sulfonamide; Wastewater