Biodegradation of Indanthrene Blue RS dye in immobilized continuous upflow packed bed bioreactor using corncob biochar.

The current study describes the aerobic biodegradation of Indanthrene Blue RS dye by a microbial consortium immobilized on corn-cob biochar in a continuous up-flow packed bed bioreactor. The adsorption experiments were performed without microbes to monitor the adsorption effects on initial dye decolorization efficiency. The batch experiments were carried out to estimate the process parameters, and the optimal values of pH, temperature, and inoculum volume were identified as 10.0, 30 °C, and 3.0 × 106 CFU mL-1, respectively. During the continuous operation, the effect of flow rate, initial substrate concentration, inlet loading rate of Indanthrene Blue RS on the elimination capacity, and its removal efficiency in the bioreactor was studied. The continuous up-flow packed bed bioreactor was performed at different flow rates (0.25 to 1.25 L h-1) under the optimal parameters. The maximum removal efficiency of 90% was observed, with the loading rate varying between 100 and 300 mg L-1 day-1. The up-flow packed bed bioreactor used for this study was extremely useful in eliminating Indanthrene Blue RS dye using both the biosorption and biodegradation process. Therefore, it is a potential treatment strategy for detoxifying textile wastewater containing anthraquinone-based dyes.

Enhanced degradation of anthraquinone dyes by microbial monoculture and developed consortium through the production of specific enzymes.

The current study investigates the decolorization of Indanthrene Blue RS dye and the optimization of process parameters needed for effective decolorization by the bacterial consortium. The pure culture of strain TS8, PMS, and NCH has been isolated from the textile wastewater sample collected from local textile processing units outlet and dye contaminated soil from Odisha, India. A bacterial consortium-BP of Bacillus flexus TS8 (BF), Proteus mirabilis PMS (PM), and Pseudomonas aeruginosa NCH (PA) were developed. The physicochemical parameters were optimized to attain maximum decolorization efficacy. Degradation of Indanthrene Blue RS and the formation of metabolites were confirmed through UV-vis spectroscopy, FT-IR, and GC-MS analysis. The developed consortium-BP showed an enhanced decolorization of Indanthrene Blue RS dye with an Average decolorization rate of 11,088 µg h-1 within 9 h compared to the individual strains under aerobic conditions. The supplementation of agricultural residual wastes showed increased decolorization efficiency of consortium-BP. Higher reduction in TOC and COD removal (≥ 80%) determined the mineralization of Indanthrene Blue RS by consortium-BP. Significant induction of various oxidoreductive enzymes in consortium-BP compared to that of Individual strains indicates their involvement in the overall decolorization and degradation process, with the higher protein concentration in the intracellular enzymes. Studies on the phytotoxicity effect revealed the non-toxic nature of the degraded products formed on mineralization of Indanthrene Blue RS by consortium-BP. This study represents a new approach for enhanced biodegradation using consortium-BP in treating textile wastewaters containing anthraquinone dyes.

Response surface methodology mediated optimization of Indanthrene Blue RS by a novel isolated bacterial strain Bacillus flexus TS8.

The enhanced decolorization and detoxification of Indanthrene Blue RS dye, under aerobic conditions, by a novel isolated anthraquinone-degrading bacterium, Bacillus flexus TS8, has been presented in this paper. The optimal decolorization conditions were determined by response surface methodology based on Box-Behnken design. The results indicated that the strain TS8 possessed the highest decolorization efficacy at pH 10.26, temperature 30.97 ºC and an inoculum size of 10.48% (v/v). It also revealed that about 98.01% of 100 mg/L of Indanthrene Blue RS could be decolorized within 24 hr under these optimized conditions. The subsequent degradation of the dye and the formation of metabolites were studied using analytical techniques such as UV-Vis spectroscopy, FTIR, and ESI/LC-MS analysis. The UV-Vis analysis of the colorless bacterial cells demonstrated that Bacillus sp. TS8 possessed this decolorizing activity through biodegradation. The degraded products obtained from ESI/LC-MS analysis were identified as 1-hydroxyanthracene-9, 10-dione (m/z-224), 1, 4-di-hydroxyanthracene-9, 10-dione (m/z-240), and phthalic acid (m/z-168). This study investigated the highest decolorization efficacy of strain TS8 to be utilized in the biological treatment of wastewaters containing anthraquinone dyes. PRACTITIONER POINTS: Enhanced decolorization of anthraquinone dye wastewater. Ninety-eight percentage of dye decolorization was obtained within 24 hr. Optimization of process parameters through the response surface methodology. ESI/LC-MS analysis identified phthalic acid as the end product of Indanthrene Blue RS degradation. Degradation pathway for Indanthrene Blue RS is outlined.