Enhanced Dissipation of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) in Soil by the Bioaugmentation with Newly...

The presented study investigated the possibility of using the Acinetobacter johnsonii MC5 strain, isolated from raw sewage by the enrichment culture method, in the bioremediation of soil contaminated with selected NSAIDs, i.e., ibuprofen (IBF), diclofenac (DCF), and naproxen (NPX), using the bioaugmentation technique. The degradation potential of A. johnsonii MC5 was first evaluated using a mineral salt medium containing drugs as the only sources of carbon and energy. The results show that the strain MC5 was capable of utilizing the tested compounds in medium, indicating that the drugs might be metabolically degraded. IBF and NPX were degraded with a similar rate and DT50 values were determined to be approximately 5 days, while the degradation process for DCF was slower, and the DT50 value was about 5 times higher (22.7 days) compared to those calculated for IBF and NPX. Bioaugmentation of non-sterile soil with A. johnsonii MC5 increased the rate of disappearance of the tested drugs, and DT50 values decreased 5.4-, 3.6-, or 6.5-fold for IBF, DCF, or NPX, respectively, in comparison with the values obtained for the soil with indigenous microorganisms only. The obtained results suggest that A. johnsonii MC5 may have potential for use in bioremediation of NSAID-contaminated soils; however, detailed studies are needed before using this strain in such process on a larger scale.