Bioremediation of anthraquinone dye reactive blue 19 by halo-acido-alkaliphilic bacterial consortia.

Water pollution caused by dyes is a global problem. This study examines the effect of four recently created bacterial consortia on bioremediation of Reactive Blue 19 (RB 19, a recalcitrant, mutagenic, and carcinogenic anthraquinone dye) in a range of environmental and nutritional circumstances. Color reductions were significantly (P < 0.001) influenced by both the bacterial consortia and the factors tested. Under optimal conditions (Salt-optimized broth with 2% glycerol, 0.5% yeast extract, 2.5% NaCl, 75 mg/L dye, pH 8, 28 °C, 72 h incubation, and microaerophilic), 94.0, 96.7, 97.9, and 99.7% decolorization achieved by C1 (Pseudomonas fluorescens ENSG304, Klebsiella pneumoniae ENSG303, Acinetobacter lwoffii ENSG302, and Vitreoscilla sp. ENSG301), C2 (Enterobacter asburiae ENSD102, E. ludwigii ENSH201, and Escherichia coli ENSD101), C3 (ENSD102, ENSG301, and Bacillus thuringiensis ENSW401), and C4 (ENSD101, ENSH201, and ENSW401), respectively. Out of all consortia, C4 performed the best across all conditions, followed by C3. Under favorable conditions, these consortia generated high amounts of lignin peroxidase, laccase, and NADH-DCIP reductase, while enzyme expression was significantly repressed under unfavorable conditions. A remarkable amount of chemical oxygen demand (82.9 to 89.4%) and total organic carbon (66.4 to 71.6%) was decreased by inoculation of these consortia. The biodegradation of RB 19 was validated by Fourier Transform Infrared (FTIR) and UV-Vis spectrum studies. The biodegraded compounds did not inhibit plant and microbial growth, suggesting detoxification. These findings suggest that the studied consortia, particularly C4, exhibit promising potential for RB 19 decolorization under the tested conditions.