How Streptomyces Bacteria Break Down and Remove Color from Various Textile Dyes

Jim Crocker
15th June, 2024

How Streptomyces Bacteria Break Down and Remove Color from Various Textile Dyes

Image Source: Natural Science News, 2024

Key Findings

  • The study by the National Research Centre in Egypt evaluated the effectiveness of Streptomyces albidoflavus 3MGH in decolorizing and degrading three azo dyes: RO 122, DB 15, and DB 38
  • S. albidoflavus 3MGH achieved up to 61.38% decolorization of the dyes within 5 days under optimal conditions (35°C, pH 6, sucrose as a carbon source, and beef extract as a nitrogen source)
  • The treatment with S. albidoflavus 3MGH resulted in significant reductions in total organic carbon, indicating substantial breakdown of complex dye molecules into simpler, less harmful compounds
Efficiently mitigating and managing environmental pollution caused by the improper disposal of dyes and effluents from the textile industry is of great importance. This study by the National Research Centre evaluated the effectiveness of Streptomyces albidoflavus 3MGH in decolorizing and degrading three different azo dyes, namely Reactive Orange 122 (RO 122), Direct Blue 15 (DB 15), and Direct Black 38 (DB 38)[1]. Azo dyes are synthetic dyes characterized by their azo bonds (N=N) and are widely used in the textile industry. However, their improper disposal can lead to severe environmental pollution, affecting both aquatic and terrestrial ecosystems[2]. The study aimed to find an efficient and eco-friendly method to decolorize and degrade these dyes. The researchers used various analytical techniques to analyze the degraded byproducts of the dyes. Fourier Transform Infrared (FTIR) spectroscopy was employed to identify changes in functional groups, High-Performance Liquid Chromatography (HPLC) was used to analyze the retention time of degraded metabolites, and Gas Chromatography-Mass Spectrometry (GC-MS) was used to propose degradative pathways based on mass/charge and molecular weight. S. albidoflavus 3MGH demonstrated a strong capability to decolorize RO 122, DB 15, and DB 38, achieving up to 60.74%, 61.38%, and 53.43% decolorization within 5 days at a concentration of 0.3 g/L, respectively. The optimal conditions for the maximum decolorization of these azo dyes were found to be a temperature of 35°C, a pH of 6, sucrose as a carbon source, and beef extract as a nitrogen source. This aligns with earlier studies where specific conditions were found to optimize the activity of dye-degrading enzymes[3][4]. Additionally, after optimization of the decolorization process, treatment with S. albidoflavus 3MGH resulted in significant reductions of 94.4%, 86.3%, and 68.2% in the total organic carbon of RO 122, DB 15, and DB 38, respectively. This indicates a substantial breakdown of complex dye molecules into simpler, less harmful compounds. The specific activity of the laccase enzyme, one of the mediating enzymes of the degradation mechanism, was found to be 5.96 U/mg. Laccase enzymes have been previously identified as effective in the decolorization of textile dyes, as seen in the study involving B. amyloliquefaciens[3]. FT-IR spectroscopy analysis of the degraded metabolites showed specific changes and shifts in peaks compared to the control samples, indicating the breakdown of the dye molecules. GC-MS analysis revealed the presence of metabolites such as benzene, biphenyl, and naphthalene derivatives. These findings are consistent with earlier studies where GC-MS was used to identify degraded metabolites and propose degradation pathways[2][5]. Overall, this study demonstrated the potential of S. albidoflavus 3MGH for the effective decolorization and degradation of different azo dyes. The findings were validated through various analytical techniques, shedding light on the biodegradation mechanism employed by this strain. This research contributes to the growing body of evidence supporting the use of microbial strains for the eco-friendly treatment of textile effluents, offering a promising solution to mitigate environmental pollution caused by azo dyes.

EnvironmentBiotechBiochem

References

Main Study

1) Exploring the decolorization efficiency and biodegradation mechanisms of different functional textile azo dyes by Streptomyces albidoflavus 3MGH

Published 14th June, 2024

https://doi.org/10.1186/s12866-024-03347-9

Related Studies

2) Biodegradation of textile azo dyes by textile effluent non-adapted and adapted Aeromonas hydrophila.

https://doi.org/10.1016/j.envres.2020.110643

3) Optimization of spore laccase production by Bacillus amyloliquefaciens isolated from wastewater and its potential in green biodecolorization of synthetic textile dyes.

https://doi.org/10.1080/10826068.2020.1786698

4) Ecofriendly biodegradation of Reactive Black 5 by newly isolated Sterigmatomyces halophilus SSA1575, valued for textile azo dye wastewater processing and detoxification.

https://doi.org/10.1038/s41598-020-69304-4

5) Development and characterization of a halo-thermophilic bacterial consortium for decolorization of azo dye.

https://doi.org/10.1016/j.chemosphere.2021.129916


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