Biodegradation and detoxification of textile dye Disperse Red 54 by Brevibacillus laterosporus and determination of its metabolic fate

• The decolorization of Disperse Red 54 was studied using a potent bacterial strain.
• Peptone and yeast extract were good nitrogen sources that accelerate decolorization.
• Different oxido-reductive enzymes were found to be involved in decolorization.
• Disperse Red 54 were biodegraded into final product-N-(1λ3-chlorinin-2-yl)acetamide.
• Metabolic and phytotoxicity studies suggested the detoxification of Disperse Red 54.

Bioremediation is one of the milestones achieved by the biotechnological innovations. It is generating superior results in waste management such as removal of textile dyes, which are considered xenobiotic compounds and recalcitrant to biodegradation. In the present bioremedial approach, Brevibacillus laterosporus was used as an effective microbial tool to decolorize disperse dye Disperse Red 54 (DR54). Under optimized conditions (pH 7, 40°C), B. laterosporus led to 100% decolorization of DR54 (at 50 mg L−1) within 48 h. Yeast extract and peptone, supplemented in medium enhanced the decolorization efficiency of the bacterium. During the decolorization process, activities of enzymes responsible for decolorization, such as tyrosinase, veratryl alcohol oxidase and NADH–-DCIP reductase were induced by 1.32-, 1.51- and 4.37-fold, respectively. The completely different chromatographic/spectroscopic spectrum of metabolites obtained after decolorization confirmed the biodegradation of DR54 as showed by High pressure liquid chromatography, High pressure thin layer chromatography and Fourier transform infrared spectroscopy. Gas chromatography–Mass spectroscopy studies suggested the parent dye was biodegraded into simple final product, N-(1λ3-chlorinin-2-yl)acetamide. Phytotoxicity study suggested that the metabolites obtained after biodegradation of DR54 were non-toxic as compared to the untreated dye signifying the detoxification of the DR54 by B. laterosporus.