Quantitative Assessment, Molecular Docking and Novel Metabolic Pathways Reveal the Interaction Mechanisms between Norfloxacin biodegradation and Environmental Implications

Abstract

Norfloxacin (NOR) is widely used in medicine and animal husbandry, but its accumulation in the environment poses a substantial threat to ecological and human health. Traditional physical, chemical, and rudimentary biological methods often fall short in mitigating NOR contamination, necessitating innovative biological approaches. This study proposes an engineered bacterial consortium found in marine sediment as a strategy to enhance NOR degradation through inter-strain co-metabolism of diverse substrates. Strategically supplementing the engineered bacterial consortium with exogenous carbon sources and metal ions boosted the activity of key degradation enzymes like laccase, manganese peroxidase, and dehydrogenase. Iron and amino acids demonstrated synergistic effects, resulting in a remarkable 70.8% reduction in NOR levels. The innovative application of molecular docking elucidated enzyme interactions with NOR, uncovering potential biodegradation mechanisms. Quantitative assessment reinforced the efficiency of NOR degradation within the engineered bacterial consortium. Four metabolic routes are herein proposed: acetylation, defluorination, ring scission, and hydroxylation. Notably, this study discloses distinctive, co-operative metabolic pathways for NOR degradation within the specific microbial community. These findings provide new ways of understanding and investigating the bioremediation potential of NOR contaminants, which may lead to the development of more sustainable and effective environmental management strategies. Environmental ImplicationsNorfloxacin (NOR), a representative fluoroquinolone antibiotic (FQs), has experienced widespread use, leading to its substantial environmental accumulation and subsequent ecological and health risks. This research endeavored to augment the elimination of NOR by harnessing bacterial co-metabolism processes through exogenous stimulation of microbial consortia. Moreover, it aimed to clarify NOR's degradation mechanisms via molecular docking investigations coupled with metabolite analyses. This integrative methodology presents a novel and promising research strategy for ensuring long-term ecosystem well-being through the effective remediation of environmental contaminants.