DUGi

Enhanced sulfamethoxazole degradation through ammonia oxidizing bacteria co-metabolism and fate of transformation products

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The occurrence of the widely-used antibiotic sulfamethoxazole (SFX) in wastewaters and surface waters has been reported in a large number of studies. However, the results obtained up-to-date have pointed out disparities in its removal. This manuscript explores the enhanced biodegradation potential of an enriched culture of Ammonia Oxidizing Bacteria (AOB) towards SFX. Several sets of batch tests were conducted to establish a link between SFX degradation and specific ammonia oxidation rate. The occurrence, degradation and generation of SFX and some of its transformation products (4-Nitro SFX, Desamino-SFX and N4-Acetyl-SFX) was also monitored. A clear link between the degradation of SFX and the nitrification rate was found, resulting in an increased SFX removal at higher specific ammonia oxidation rates. Moreover, experiments conducted under the presence of allylthiourea (ATU) did not present any removal of SFX, suggesting a connection between the AMO enzyme and SFX degradation. Long term experiments (up to 10 weeks) were also conducted adding two different concentrations (10 and 100 μg/L) of SFX in the influent of a partial nitrification sequencing batch reactor, resulting in up to 98% removal. Finally, the formation of transformation products during SFX degradation represented up to 32%, being 4-Nitro-SFX the most abundant

This study has received funding from the People Program (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7/2007-2013, under REA agreement 289193-Project SANITAS and the European Comission FP7-PEOPLE-2011-CIG 303946 project, and from Waterfate project (CTM2012-38314-C02-01). This publication reflects only the author’s views and the European Union is not liable for any use that may be made of the information contained therein. Elissavet Kassotaki acknowledges the FI fellowship (2015FI_B 00454) from the Catalan Government. Maite Pijuan acknowledges the Ramon y Cajal research fellowship (RYC-2009-04959) from the Spanish Ministry of Economy and Competitiveness. Authors acknowledge the support from the Economy and Knowledge Department of the Catalan Government through a Consolidated Research Group (2014 SGR 291) - Catalan Institute for Water Research.

Elsevier