Bioremediation of Reactive Red 120 by Enterobacter cloacae VITPBS14: Integrated in vitro and in silico approaches

The diazo dye Reactive Red 120 (RR120), widely used in textile industry poses severe ecotoxicological risks due to its recalcitrance, structural stability, and carcinogenicity. Microbial bioremediation offers a sustainable alternative for the detoxification of this xenobiotic compound, utilizing enzymatic systems for targeted metabolic cleavage and removal. This study investigated the biodegradation of RR120 using indigenous bacterial strains isolated from textile effluents. Initial screening identified Enterobacter cloacae VITPBS14 as the most effective isolate, achieving maximum decolorization within 72 h which was further enhanced by optimized carbon and nitrogen supplementation. Statistical optimization using Box–Behnken experimental design significantly enhanced the degradation efficiency. The presence of laccase and azo-reductase enzymes indicates their role in degradation process. Metabolite analysis using UV–Vis spectroscopy, FT-IR, HPLC, and LC-HRMS enabled identification of degradation products and elucidation of a probable degradation pathway. The toxicological assessment of the degraded metabolite confirms the non-toxic nature of the compound. Additionally, in silico molecular docking studies provided insights into enzyme-substrate interactions and validated the proposed degradation mechanism. Overall, the result highlights the potential of E. cloacae VITPBS14 as an effective candidate for sustainable azo dye bioremediation. • E. cloacae VITPBS14 efficiently degrades diazo dye Reactive Red 120. • BBD/RSM optimization of environmental parameters maximized degradation. • Metabolites identified by LC-HRMS; detailed degradation pathway proposed. • Ecotoxicity assays confirmed reduced toxicity of the degradation products. • Molecular docking revealed binding of Reactive Red 120 with key bacterial enzymes.