Degradation of Diclofenac and Ketoprofen by Bacillus Paralicheniformis HAS-1, Strain Isolated From a Soda Lake Sediment
摘要
Emerging pollutants, such as diclofenac and ketoprofen, are substances of concern because of their toxicity and ecosystemic damage. In this study, Bacillus paralicheniformis HAS-1 was found to be a potential biodegrader of diclofenac and ketoprofen. The strain was isolated from soda lake sediment and its growth conditions were determined at different concentrations of NaCl (0-20)% at pH 7, and at different pH values (5–12) using the optimal NaCl concentration. The complete genome was sequenced using the MinION platform to perform taxonomic assignment of the bacteria and was annotated using RAST. Growth was determined using diclofenac, ketoprofen, and glucose as sole carbon sources. The degradation capability of the strain was determined using HPLC after 15 days of exposure to each drug. Secondary metabolites were detected using UPLC-QToF. The results showed that the strain tolerated a maximum of 10% NaCl and pH values between 5-12. Likewise, genome sequencing identified the strain as Bacillus paralicheniformis and genomic annotation revealed different genes encoding enzymes involved in the metabolism of aromatic compounds. The strain grew in diclofenac and ketoprofen as the only sources of carbon, although the biodegradation experiment was performed using co-metabolism with glucose. The degradation of diclofenac and ketoprofen was 38.88% and 59.78%, respectively, and the produced secondary metabolites and encoding enzymes suggest a degradation pathway mediated by hydroxylation reactions followed by the action of monooxygenase or carboxylase enzymes. This strain has potential use in bioremediation processes involving diclofenac and ketoprofen, which are currently unknown to this bacterium.
Graphical Abstract