Biodegradation of non-steroidal anti-inflammatory drug loxoprofen by a hyper lignin-degrading fungus Phanerochaete sordida YK-624 under non-ligninolytic conditions.

Loxoprofen has been widely used as a non-steroidal anti-inflammatory drug globally and it can also persist in the environment. Although it is known to be a non-toxic drug, its presence may still pose a potential risk to organisms in the environment. Here, the hyper lignin-degrading fungus Phanerochaete sordida YK-624 was used to study the degradation of loxoprofen. This fungus showed excellent loxoprofen biodegradation ability with 90.4% and 93.4% after one day of incubation at lower concentrations of 0.01 and 0.005 mM, respectively. And at a higher concentration of 0.1 mM, a significant removal of 94.2% was also observed after 10 days of incubation. In this study, four metabolites were isolated and determined by HR-ESI-MS and NMR. Furthermore, LC/MS analysis suggested the presence of intermediate hydroxy loxoprofen. In addition, loxoprofen-OH was also identified as a metabolite of loxoprofen through comparison with the synthesized compounds. In this metabolism of loxoprofen, cytochrome P450 may play a significant role. Interestingly, P. sordida YK-624 showed enantioselectivity in the degradation process of loxoprofen. By these results, three degradation pathways of loxoprofen by P. sordida YK-624 were hypothesized. To the best of our knowledge, this is the first report describing the potential degradation mechanisms of loxoprofen by a white-rot fungus.