title: Biodegradability of fluoxetine, mefenamic acid, and metoprolol using different microbial consortiums.
abstract: The biodegradation of fluoxetine, mefenamic acid, and metoprolol using ammonium-nitrite-oxidizing consortium, nitrite-oxidizing consortium, and heterotrophic biomass was evaluated in batch tests applying different retention times. The ammonium-nitrite-oxidizing consortium presented the highest biodegradation percentages for mefenamic acid and metoprolol, of 85 and 64% respectively. This consortium was also capable to biodegrade 79% of fluoxetine. The heterotrophic consortium showed the highest ability to biodegrade fluoxetine reaching 85%, and it also had a high potential for biodegrading mefenamic acid and metoprolol, of 66 and 58% respectively. The nitrite-oxidizing consortium presented the lowest biodegradation of the three pharmaceuticals, of less than 48%. The determination of the selected pharmaceuticals in the dissolved phase and in the biomass indicated that biodegradation was the major removal mechanism of the three compounds. Based on the obtained results, the biodegradation kinetics was adjusted to pseudo-first-order for the three pharmaceuticals. The values of kbiolfor fluoxetine, mefenamic acid, and metoprolol determined with the three consortiums indicated that ammonium-nitrite-oxidizing and heterotrophic biomass allow a partial biodegradation of the compounds, while no substantial biodegradation can be expected using nitrite-oxidizing consortium. Metoprolol was the less biodegradable compound. The sorption of fluoxetine and mefenamic acid onto biomass had a significant contribution for their removal (6-14%). The lowest sorption coefficients were obtained for metoprolol indicating that the sorption onto biomass is poor (3-4%), and the contribution of this process to the global removal can be neglected.
authors.affiliation: National Autonomous University of Mexico, Campus IMTA, Paseo Cuauhnáhuac 8532, Progreso, 62550, Jiutepec, Morelos, Mexico.
authors.forename: Yolanda Flores
authors.initials: YF
authors.lastname: Velázquez
authors.affiliation: Mexican Institute of Water Technology, Paseo Cuauhnáhuac 8532, Progreso, 62550, Jiutepec, Morelos, Mexico. petiam@tlaloc.imta.mx.
authors.forename: Petia Mijaylova
authors.initials: PM
authors.lastname: Nacheva
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors; D005473:Fluoxetine / Q000032:analysis*; D052836:Heterotrophic Processes; D007700:Kinetics; D008528:Mefenamic Acid / Q000032:analysis*; D008790:Metoprolol / Q000032:analysis*; D059013:Microbial Consortia; D010084:Oxidation-Reduction; D012722:Sewage; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D012722:Sewage; D014874:Water Pollutants, Chemical; D005473:Fluoxetine; D008528:Mefenamic Acid; D008790:Metoprolol
keywords: Biodegradation; Microbial consortiums; Pharmaceutical compounds; Sorption