Amoxicillin Biodegradation with Bacillus subtilis and Pseudomonas aeruginosa: Characterization of Relevant Degradation Products

The widespread use of antibiotics can result in the release of a large number of residues into the environment. In order to reduce the exposure risk, considerable research has been carried out in the field of antibiotic residues. We aim to explore the possibilities of antibiotic amoxicillin biodegradation in laboratory scale by adding microbiological cultures, Pseudomonas aeruginosa (Gram-negative) and Bacillus subtilis (Gram-positive), which are a type of bacteria that are commonly found in the environment, such as in soil and water. Apart from the degradation itself, special attention was paid to the identification of antibiotic residues. The biodegradation process was investigated, revealing a 99.2 % degradation efficiency at amoxicillin concentration of 0.2 mg mL-1, and four degradation products were identified. For reaction monitoring and identification of degradation products, UHPLC and LC-MS analyses were performed. Furthermore, to provide additional evidence, the products were independently synthesized and then compared spectrometrically with the obtained biodegradation products. These results could provide new aspects to the behavior of amoxicillin, and pave the way for further monitoring and studies of its residues in the environment.