In vitro and In silico Studies on the Removal of Methyl Orange from Aqueous Solution Using Oedogonium subplagiostomum AP1

The present study aims to investigate the potential of Oedogonium subplagiostomum AP1 in the removal of methyl orange from aqueous solution. The effects of process parameters, namely, dye concentration, biosorbent concentration, pH and contact time on adsorption were optimised using RSM. The predictions of the model output specified that process parameters influenced responses at a confidence level of 95% (P < 0.05). Optimum conditions for methyl orange removal (97%) was obtained at pH 6.5, contact time of 5.5 days, algal dose of 400 mg/L and dye concentration of 500 mg/L. Adsorption isotherm, kinetics and thermodynamic studies were conducted to assess the decolourisation efficiency. The results indicated that Langmuir isotherm and pseudo-second-order kinetic models best fitted the experimental data. The thermodynamic parameters indicated that methyl orange biosorption onto alga is spontaneous, favourable and exothermic in nature. The biosorbent-adsorbate interactions were characterised using UV-Vis, FT IR, SEM with EDX and XRD. The reuse potential of treated dye solution was assessed by dyeing fabrics. The physical properties of fabrics dyed using algae-treated water are comparable with that of tap water-dyed fabric proving the reuse potential of treated water in textile industries. The algal biomass subjected to composting diminishes the level of pollution. In silico study was performed to observe the interaction between methyl orange (ligand) and receptor protein (azoreductase) which plays an important role in the biodegradation of textile dyes. Thus, the results showed that Oedogonium subplagiostomum AP1 could be employed as an efficient and eco-friendly biosorbent for the removal of methyl orange.