Removal of Ibuprofen from Contaminated Water by Bioaugmentation with Novel Bacterial Strains Isolated from Sewage Sludge

Ibuprofen (IBP), one of the most consumed drugs in the world, is only partially removed in Wastewater Treatment Plants (WWTPs). Its presence in effluents and sewage sludge introduces IBP into the environment. It is imperative to continue research on IBP degraders that can be used in the future to eliminate IBP at the WWTP level. This study describes the use of nine specific IBP-degrading bacteria isolated from sewage sludge (<i>Achromobacter denitrificans</i>, <i>Bordetella petrii</i>, <i>Brucella tritici</i>, <i>Curtobacterium flaccumfaciens</i>, <i>Microbacterium paraoxydans</i>, <i>Pseudomonas citronellolis</i>, <i>Pseudomonas nitroreducens</i>, <i>Shinella zoogloeoides</i>, <i>Stenotrophomonas acidaminiphila</i>) for the removal of IBP from water. Their half-maximal inhibitory concentration of IBP for bacterial growth (IC₅₀) revealed a high level of IBP tolerance. Degradation of IBP (10 mg L^-1) was effective for all the strains using glucose as a secondary substrate. Seven of the nine strains were shown to be IBP degraders for the first time by our research group, highlighting <i>A. denitrificans</i> CSW15, with almost 47% IBP degraded, and <i>C. flacumfaciens</i> CSW18, with 32.2% after 28 days. Three IBP transformation products were identified: 1-hydroxyibuprofen (1-OH-IBP), 2-hydroxyibuprofen (2-OH-IBP), and carboxyibuprofen (CBX-IBP). A comparison of the effectiveness of IBP degradation by the nine isolates with most other IBP-degrading bacteria previously reported was carried out.