Aerobic degradation of ketoprofen by marine consortia: Fenton-like reaction and degradation pathway.

Ketoprofen (KTP) as a non-steroidal anti-inflammatory drug has been detected in coastal environment due to its wide usage. However, little information is available about the fate of KTP in marine environment. In the present study, the aerobic degradation of 20 mg L-1 KTP using the enriched marine consortia was investigated. Results showed that CA consortium cultured with casamino acids exhibited a higher KTP-degrading ability than those cultured with glucose, yeast extract and mixed vitamins. During CA consortium-mediated degradation of KTP, additional casamino acids resulted in the production of H2O2 and OH. Fe(III) could be also reduced to Fe(II) by CA consortium. This result indicated the occurrence of Fenton-like reaction. Further studies found that both biogenic Fenton-like reaction and enzyme-catalyzed reactions were involved in the initial hydroxylation reaction of KTP, then the subsequent mineralization of KTP was only performed via enzyme-catalyzed reactions. High-throughput sequencing analysis showed that Halomonas, Marinobacter, Owenweeksia and Oceanimonas were significantly enriched in CA consortium. As these genera contain amino acid oxidases, and the former two genera are capable of reducing Fe(III), it is assumed that these genera participated in biogenic Fenton-like reaction. The involvement of biogenic Fenton-like reaction provides a new insight into understanding the fate of KTP and other similar organic pollutants in marine environment containing amino acids and iron.