Enhanced biodegradation of modified fluoroquinolone for aerobic, facultative, and anaerobic processes using quantitative structure-activity relationship, molecular docking, and molecular dynamics

Abstract

Molecular docking was used to calculate the docking scores of fluoroquinolones (FQs) and manganese peroxidase isolated from Phanerochaete chrysosporium, cytochrome oxidase isolated from Paracoccus denitrificans, and oxidoreductase isolated from Candidatus Kuenenia stuttgartiensis, which represented the aerobic, facultative, and anaerobic biodegradability of FQs, respectively. The comprehensive index (CI) of the above three sets of docking scores was calculated using the averaging method to characterize the aerobic, facultative, and anaerobic biodegradation of FQs. Using CI as a dependent variable, a comprehensive aerobic, aerobic, and anaerobic biodegradation CoMSIA model of FQs was constructed. Taking gatifloxacin (GAT) as the target molecule and using molecular modification information, 25 FQ derivatives suitable for aerobic, facultative, and anaerobic biodegradation were designed. After evaluating the environmental friendliness (bioconcentration and photodegradability) and the functional characteristics (genotoxicity) of FQs, six derivatives were finally screened. The combined biodegradation of 1-butylbenzene-3-fluorine-GAT in six derivatives was increased by 14.06 %, and its performance under aerobic, facultative, and anaerobic biodegradation conditions was increased by 31.33 %, 36.54 %, and 35.50 %, respectively. This improvement in the performance was in line with the equal weighting set by averaging. Molecular dynamic calculations showed that the binding energy (Δ Gb) of 1-butylbenzene-3-fluorine-GAT was lower than that of GAT (the lower the value of Δ Gb, the stronger the binding ability), indicating that it had a stronger affinity for degrading enzymes.