Sulphonated azo dye decolorization by Alcaligenes faecalis subsp. phenolicus MB207: Insights from laboratory and computational analysis

Abstract

Microbial decolorization of azo dyes, mediated by an enzymatic mechanism is an intricate cost-effective, and eco-friendly treatment method of genotoxic azo pollutants. Scientists are on the constant lookout for microbes, enzymes, and mechanisms that could aid remediation of the environment at a fast pace. Alcaligenes faecalis subsp. phenolicus MB207 is one such bacteria, consisting of azoreductase (AzoR) and laccase/multicopper oxidase enzyme responsible for sulphonated mono-azo dye (Methyl orange) and di-azo dye (Congo red) degradation. AzoR degrades dyes by a ping-pong setup while multicopper oxidase achieves this through a non-specified radical approach. We have coupled experimental analysis with bioinformatics for deciphering intricacies of this procedure in tiny scale enzymatic machines of this biotope. The degradation assays were followed by molecular docking of the enzyme-substrate complexes. Key anchoring bonds were detected and mapped H-bonding, electron exchange, ionic interactions, as well as hydrophobic interactions, provided insights into dye-enzyme and NADH-enzyme binding. This study establishes a foundation of the molecular basis of dye interaction with azoR and multicopper oxidase in A. facealis subsp. phenolicus MB207.