Abstract
Background: Acid Blue 113 (AB113) is a typical azo dye, and the resulting wastewater is toxic and difficult to remove. Methods: The experimental culture was set up for the biodegradation of the azo dye AB113, and the cell growth and dye decolorization were monitored. Transcriptome sequencing was performed in the presence and absence of AB113 treatment. The key pathways and enzymes involved in AB113 degradation were found through pathway analysis and enrichment software (GO, EggNog and KEGG). Results: S. melonis B-2 achieved more than 80% decolorization within 24 h (50 and 100 mg/L dye). There was a positive relationship between cell growth and the azo dye degradation rate. The expression level of enzymes involved in benzoate and naphthalene degradation pathways (NADH quinone oxidoreductase, N-acetyltransferase and aromatic ring-hydroxylating dioxygenase) increased significantly after the treatment of AB113. Conclusions: Benzoate and naphthalene degradation pathways were the key pathways for AB113 degradation. NADH quinone oxidoreductase, N-acetyltransferase, aromatic ring-hydroxylating dioxygenase and CYP450 were the key enzymes for AB113 degradation. This study provides evidence for the process of AB113 biodegradation at the molecular and biochemical level that will be useful in monitoring the dye wastewater treatment process at the full-scale treatment.
Highlights
S. melonis B-2 was grown in the presence of Acid Blue 113 (50 mg/L) and the absence of the dye
We successfully selected a bacterium (S. melonis B-2) for the efficient dye decolorization of the azo dyes, which are a major product of dye production
It was concluded that all the data of decolorization, cell growth and FT-IR spectra collectively provided consistent evidence for the azo dye decolorization and potential mineralization of the dye by the stably maintained culture
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Different classes of dyes are used in numerous industries, including the rubber, textile, cosmetic, plastic, leather, food, and paper manufacturing industries. Various dyes are seen in the wastewater discharged from these industries [1]. The largest contributor to dye wastewater is the textile industry, which is responsible for two-thirds of the total production of dye wastes due to the high quantities of water used in the dyeing processes [2–5]. The major problem is the unfixed dyes that remain in the wastewater after textile processing [5]. Approximately 15–30% of the dyestuff fails to bind to the fibers and is released into the environment [6]
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