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Biodegradation of synthetic dye using partially purified and characterized laccase and its proposed mechanism

Ghobadi Nejad, Z ; Sharif University of Technology | 2019

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  1. Type of Document: Article
  2. DOI: 10.1007/s13762-019-02226-5
  3. Publisher: Center for Environmental and Energy Research and Studies , 2019
  4. Abstract:
  5. The supernatant obtained from the extracellular laccase produced by Phanerochaete chrysosporium was used as the enzyme source to conduct a partial purification, characterization and dye decolorization study. The partially purified enzyme was stable in the pH range of 3–5 and showed an optimum activity at pH 4.0, using guaiacol as a substrate. Laccase stability of pH was determined and discovered to retain 100% of its activity at a pH of 4.0 after 2 h. The maximum enzyme activity was obtained between 30 and 50 °C. The maximum velocity and Michaelis constant were calculated as 3.171 µM−1·min and 1628.23 µM, respectively. The enzyme was activated by Fe2+, Zn2+, Ca2+ and Cu2+, while Hg2+, Mn2+, Co2+, Mg2+, Cd2+, Ni2+ reduced the laccase activity. The partially purified enzyme was strongly inhibited by 1 mM of NaN3 and sodium thioglycolate. Among the eight different dyes (Malachite green, Safranin, Crystal violet, Methylene blue, Eriochrome black T, Methyl red, Methyl orange, Rhodamine B and Nigrosin), the enzyme showed highly efficient decolorizing activity (99%) toward Malachite green after treatment for 24 h at 30 °C. Antibacterial results showed that the product obtained by treating the dye with the enzyme is completely non-toxic to Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. High-performance liquid chromatography and mass spectroscopy analysis of the extracted product confirmed the complete biodegradation of Malachite green and Leucomalachite green. Di-benzyl methane and 4-(dimethylamino) benzaldehyde were the ultimate products identified in this research. © 2019, Islamic Azad University (IAU)
  6. Keywords:
  7. Antibacterial activity ; Decolorization ; Laccase ; Aromatic compounds ; Azo dyes ; Carbonate minerals ; Detoxification ; Dyeing ; Dyes ; Enzyme activity ; Escherichia coli ; High performance liquid chromatography ; Mass spectrometry ; Purification ; Sodium Azide ; Anti-bacterial activity ; Leucomalachite green ; Partial purification ; Phanerochaete chrysosporium ; Pseudomonas aeruginosa ; Staphylococcus aureus ; Nitrogen compounds ; Antimicrobial activity ; Bacterium ; Biodegradation ; Chemical compound ; Detection method ; Dye ; Enzyme ; Microbial activity ; Pollutant removal ; Temperature effect
  8. Source: International Journal of Environmental Science and Technology ; Volume 16, Issue 12 , 2019 , Pages 7805-7816 ; 17351472 (ISSN)
  9. URL: https://link.springer.com/article/10.1007/s13762-019-02226-5