Comparative analysis of azo dye degradation by oxidoreductase, laccase and peroxidase of Acinetobacter junii: A computational study

Abstract Textile industry releases substantial quantities of toxic azo dyes in water leading to severe environmental pollution globally. Many microbial enzymes are known to successfully oxidize the complex chemical structure of azo dyes, converting them to less toxic forms. This study gives an insight into the dye degrading abilities of three enzymes (oxidoreductase, laccase, and peroxidase) of Acinetobacter junii and focuses on their comparative analysis using computational tools. A total of six azo dyes, including Acid orange 19, Dispersed red 1, Dispersed red 13, Acid violet 7, Reactive brilliant red, and Congo red, were selected. The dye degradation was observed using molecular docking analysis. The 3D structures of enzymes were modeled using I-TASSER, and the Ramachandran plot marked these models as stable having more than 80% residues in the favorable and allowed regions. The molecular docking was followed by the selection of most stable enzyme-dye complexes based upon the binding affinities and molecular interactions. This comparative analysis revealed that oxidoreductase and laccase have significant binding affinities (>-5kcal/mol) with all azo dyes and form the most stable complexes and therefore are likely to be used for the large-scale analysis of azo dyes. These results were supported by the molecular dynamics simulations. Further experimental analysis may help the selection of suitable enzymes for large-scale bioremediation of the toxic azo dyes in an industrial setup.