Decolorization of aqueous solutions of disperse textile dyes by oxidoreductases

Abstract

The potential of three oxidoreductases, a laccase preparation of Pleurotus sajor-caju PS-2001, horseradish peroxidase (HRP) and a microbial peroxidase (MP) was evaluated for the decolorization of disperse textile dyes (CI Disperse Red 343, CI Disperse Red 167 and CI Disperse Blue 148) used in polyester dyeing. Decolorization was studied in aqueous solutions varying in dye concentration, pH, temperature, enzyme concentration and the addition of mediators HBT and syringaldazine. The best conditions found for Disperse Red 343 with laccase, HRP and MP were: 15 mg L⁻¹ dye concentration, 50°C, pH 3.0 for laccase and pH 5.0 for peroxidases. Without mediator, the highest decolorizaton results (38.5% and 58.6%) were achieved with the highest tested concentrations of laccase (10 U mL⁻¹) and HRP (89.7 U mL⁻¹), respectively, but no significant difference in decolorization was found for the tested MP concentrations (29.9–89.7 U mL^‐1). HBT or syringaldazine increased decolorization with peroxidases significantly, but no effect was observed for the laccase. Decolorization of Disperse Red 167 (up to 15%) and Disperse Blue 148 (up to 25%) was much lower than of Disperse Red 343. With respect to enzyme concentration, the use of mediator and under the selected test conditions the laccase of P. sajor-caju PS-2001 turned out to be more efficient in disperse dye decolorization, than peroxidases HRP and MP.

Keywords::

• disperse textile dyes
• Pleurotus sajor-caju
• laccase
• peroxidase
• decolorization Introduction

Acknowledgements

This study was supported by the Regional University of Blumenau (FURB), University of Caxias do Sul (UCS), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil), Coordenadoria de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brazil), and Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS, Brazil) through financial funding and scholarships.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.