Functional and catalytic active sites prediction and docking analysis of azoreductase enzyme in Pseudomonas putida with a variety of commercially available azodyes

Ecofriendly Approach on the Removal of Reactive Orange 107 from Aqueous Solutions Using Cladophora Species as a Novel Biosorbent

The efficiency of Cladophora species for the removal of Reactive Orange 107 (RO107) from the aqueous solution was evaluated through batch adsorption studies by optimising various process parameters such as pH (3-8), dye concentration (100-500 mg/l), biosorbent concentration (100-500 mg/l), temperature (25-45 °C) and contact time (12-108 h). The results revealed that the optimum conditions for RO107 decolourisation (87%) was found on 72 h of incubation with 100 mg/l dye concentration amended with 200 mg/l biosorbent at pH 6 at 25 °C. The mechanism of dye adsorption was evaluated using isotherms, kinetics and thermodynamic models. The experimental data fitted well with Langmuir isotherm and pseudo-second-order kinetic models. Thermodynamic studies revealed that the adsorption process was endothermic, spontaneous and feasible in nature. Recovery of RO107 from the Cladophora sp. was maximum when 0.1 M HNO3 was used as an eluent. UV-Visible, FT-IR and SEM analyses reveal the interaction between the biosorbent-adsorbate and confirm the process of decolourisation by Cladophora sp. In order to evaluate the nature of the untreated and treated dye solutions, toxicological studies were conducted and the results revealed that the treated dye solution was non- toxic as compared with untreated dye solution. The results of the docking study proved that there was a substantial binding energy between RO107 and the protein (Cytochrome C6) of Cladophora sp. Hence, Cladophora sp. proves to be a promising biosorbent to decolourise RO107 and its potential can be explored in the textile sectors.

Statistical optimization for the efficacious degradation of reactive azo dyes using Acinetobacter baumannii JC359

The aim of this study is to biodegrade the reactive azo dyes- Reactive black 5 (B-GDN), Reactive red 120 (RP) and Reactive blue 19 (RNB) using bacteria Acinetobacter baumannii JC359. Optimization of the process variables such as pH, temperature, dye concentration, incubation time, inoculum volume and dynamic incubating conditions for dye decolorization were performed using One Factor At a Time (OFAT) approach. Box- Behnken Design (BBD) of Response Surface Methodology (RSM) was further used to optimize the process variables. Decolorization rates of 98.8% for B-GDN, 96% for RP and 96.2% for RNB were observed after treating with A. baumannii for 48 h using the obtained design value. UV-Visible spectrophotometry and FT-IR spectral scan of dye and degraded metabolites confirmed that biodegradation had taken place. Further, the phytotoxicity evaluation was performed with Vigna radiata seeds and the degraded metabolites proved to be non-toxic. Docking studies were performed and it was found that there was significant binding affinity between the dyes and azoreductase enzyme of A. baumannii. Thus, the biodegradation of these reactive azo dyes was found to be a suitable alternative for the effective treatment of textile dyes.