engleski

Systematic degradation of synthetic dyes with heme and flavin containing oxidoreductases

Synthetic dyes used in the textile- or pulp- and paper industry are often harmful or toxic compounds and represent a worldwide ecological problem. In the presented work we investigate an eco-friendly, enzymatic approach for dye removal. We evaluated seven different oxidoreductases for their potential to specifically decolorize and detoxify 175 industrially relevant dyes including anthraquinone-, azo-, trimethylmethane-, and indigo chromophores. Utilized enzymes were cellobiose dehydrogenase from the plant-pathogenic fungus Sclerotium rolfsii, laccases from the ascomycete Botrytis aclada and the basidiomycete Trametes pubescens, glucose oxidase from Aspergillus niger, horseradish peroxidase, manganese peroxidase from Phanerochaete chrysosporium and lignin peroxidase. Decolorization was studied at alkaline, neutral and acidic pH using a high-troughput spectroscopic assay. Absorbances of most of the investigated dyes could be reduced by at least 50% within 24 hours of incubation at room temperature. Highest rates of decolorization were observed at acidic pH for most of the enzymes. Laccase from T. pubescens efficiently degraded 85 of the 175 dyes (49%) followed by horseradish peroxidase (45%), laccase from B. aclada (23%) and cellobiose dehydrogenase (13%). Glucose oxidase (4%) was least successful, indicating that hydrogen peroxide production has little effect on the chromophores. Our results show that with a limited number of enzymes a multitude of dyes can be effectively decolorized. Further research was performed to study the chemical structure and toxic effects of the dyes and their degradation products to assess their environmental impact. Catalytic parameters of the enzymatic reactions were elucidated to define optimal application conditions for efficient dye degradation.

enzymes; textile dyes; degradation

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