Velázquez Yolanda Flores, Nacheva Petia Mijaylova
National Autonomous University of Mexico, Campus IMTA, Paseo Cuauhnáhuac 8532, Progreso, 62550, Jiutepec, Morelos, Mexico.
Mexican Institute of Water Technology, Paseo Cuauhnáhuac 8532, Progreso, 62550, Jiutepec, Morelos, Mexico.
Environ Sci Pollut Res Int. 2017 Mar;24(7):6779-6793. doi: 10.1007/s11356-017-8413-y. Epub 2017 Jan 14.
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 k for 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.
在不同保留时间的批次试验中，评估了使用亚硝酸铵氧化菌群、亚硝酸氧化菌群和异养生物质对氟西汀、甲芬那酸和美托洛尔的生物降解情况。亚硝酸铵氧化菌群对甲芬那酸和美托洛尔的生物降解率最高，分别为85%和64%。该菌群还能够对79%的氟西汀进行生物降解。异养菌群对氟西汀的生物降解能力最强，达到85%，对甲芬那酸和美托洛尔也具有较高的生物降解潜力，分别为66%和58%。亚硝酸氧化菌群对这三种药物的生物降解率最低，低于48%。对溶解相和生物质中所选药物的测定表明，生物降解是这三种化合物的主要去除机制。根据所得结果，将三种药物的生物降解动力学调整为拟一级动力学。用三种菌群测定的氟西汀、甲芬那酸和美托洛尔的k值表明，亚硝酸铵氧化菌群和异养生物质可使这些化合物部分生物降解，而使用亚硝酸氧化菌群预计不会有大量生物降解。美托洛尔是生物降解性最差的化合物。氟西汀和甲芬那酸在生物质上的吸附对其去除有显著贡献（6 - 14%）。美托洛尔的吸附系数最低，表明其在生物质上的吸附较差（3 - 4%），该过程对整体去除的贡献可忽略不计。
