Biodegradation and detoxification of textile dyes using a novel bacterium <i>Bacillus</i> sp. AS2 for sustainable environmental cleanup

Abstract

Sustainable environmental cleanup has become a widespread concept in the era of industrialization and the ever-increasing population. Due to anthropogenic activities, textile industries release a large amount of wastewater into the surrounding water bodies. In this study, a highly efficient bacterial isolate, Bacillus sp. AS2 was isolated from textile dye-contaminated soil. Different growth parameters were studied to enhance the degradation activity of the isolate. Maximum dye degradation achieved was 97.01 ± 0.36%, 92.49 ± 0.21%, and 94.23 ± 0.47% for methylene blue (MB), Congo red (CR), and malachite green (MG), respectively. The isolated bacteria were also capable of degrading (77.76 ± 0.15%) mixed dyes. Fourier-transform infra-red (FTIR) and gas chromatography–mass spectrometry (GC–MS) analysis confirmed the degradation of the textile dyes. The maximum bacterial growth rate was 0.425, 0.578, and 0.512 g d−1 in the presence of MB, CR, and MG dye, respectively. The value of µmax/Ks was 0.0154, 0.0167, and 0.0137 L mg−1 d−1 for MB, CR, and MG dye. Further, the phytotoxicity assay substantiates the eco-friendly nature of isolate Bacillus sp. AS2. Biodegradation through the selected bacterial strain can be considered the best alternative to control environmental pollution in a comparatively short time interval.