ORIGINAL PAPER Impact of biogenic substrates on sulfamethoxazole biodegradation kinetics by Achromobacter denitrificans strain PR1 P. Y. Nguyen . Gilda Carvalho . A. C. Reis . O. C. Nunes . M. A. M. Reis . A. Oehmen Received: 21 November 2016 / Accepted: 7 March 2017 Ó Springer Science+Business Media Dordrecht 2017 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 pur- poses. Complete removal of SMX occurred for all concentrations tested, i.e., 150 mg/L, 500 lg/L, 20 lg/L, and 600 ng/L. The reaction rate coefficients (k bio ) for the strain at the ng/L SMX range were: 63.4 ± 8.6, 570.1 ± 15.1 and 414.9 ± 124.2 L/gX SS Áday), 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 X SS Áday) 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 metabo- lite, which was found to be non-toxic. SMX inhibited the Vibrio fischeri luminescence after 5 min of contact, with EC 50 values 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. Keywords Wastewater Á Antibiotics Á Sulfonamide Á Co-metabolism Á Bioaugmentation Á Ecotoxicity Introduction The term antibiotic is used to denote a chemothera- peutic agent that inhibits or abolishes microbes by specific interactions with bacterial targets. In 2013, the population-weighted EU/EEA mean consumption of antibiotics was 22.4 defined daily doses/1000 inhab- itants/day, representing a continuing increase over the Electronic supplementary material The online version of this article (doi:10.1007/s10532-017-9789-6) contains supple- mentary material, which is available to authorized users. P. Y. Nguyen Á G. Carvalho (&) Á M. A. M. Reis Á A. Oehmen UCIBIO, REQUIMTE, Departamento de Quı ´mica, Faculdade de Cie ˆncias e Tecnologia, Universidade Nova de Lisboa, Caparica, 2829-516 Lisbon, Portugal e-mail: gs.carvalho@fct.unl.pt URL: http://sites.fct.unl.pt/bioeng/people/gilda-carvalho A. C. Reis Á O. C. Nunes LEPABE-Chemical Engineering Department, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal 123 Biodegradation DOI 10.1007/s10532-017-9789-6