Enhanced solar photodegradation of a plasmid-encoded extracellular antibiotic resistance gene in the presence of free chlorine
Journal
Journal of Environmental Chemical Engineering
Journal Volume
10
Journal Issue
1
Date Issued
2022
Author(s)
Abstract
The rapid spread of antibiotic resistance in aquatic environments is closely related to the prevalence of antibiotic resistance genes (ARGs). Environmental ARGs undergo some degree of solar photolysis and chlorine oxidation. This report is the first study to comprehensively investigate the solar photodegradation mechanism of a plasmid-encoded extracellular antibiotic resistance gene (pUC19) via the solar/free chlorine process. The pUC19 degradation rate via the solar/free chlorine process was significantly enhanced (1.15 ± 0.05 min?1) compared to chlorination (0.04 min?1) and direct solar photolysis (0.05 min?1) alone. Increasing the pH values from 6 to 8 resulted in a higher yield of ozone and accelerated pUC19 photodegradation. Within 20 min of the reaction time, ozone and hydroxyl radicals (?OH) were responsible for 37.5% and 55.1% of the pUC19 degradation, respectively, and the contribution of reactive chlorine species (RCS) was negligible. Degradation rates, determined by different amplicon lengths in the same segment, showed a linear correlation with amplicon length. The attack by solar/free chlorine may be nonselective because similar amplicon lengths located in different pUC19 segments (ampR and ori) showed similar degradation rates. The pUC19 lesions caused by the solar/free chlorine process were the most effective treatment for breaking DNA double bonds. An enhanced solar/free chlorine photolysis phenomenon was also observed in real swimming pool waters, despite interference and inhibition by the water matrix components, which provides valuable insight into the control of ARGs in chlorine-receiving aquatic environments. ? 2021 Elsevier Ltd
Subjects
Antibiotic resistance genes
Chlorination
Free chlorine
Photodegradation
Swimming pool
Antibiotics
Chlorine
Degradation
DNA
Genes
Lakes
Ozone
Photolysis
Swimming pools
Amplicons
Antibiotics resistance
Aquatic environments
Degradation rate
Extracellular
Photo degradation
Solar photodegradation
Solar photolysis
Type
journal article