Abstract
The azoreductase PpAzoR from Pseudomonas putida shows a broader specificity for decolourization of azo dyes than CotA-laccase from Bacillus subtilis. However, the final products of PpAzoR activity exhibited in most cases a 2 to 3-fold higher toxicity than intact dyes themselves. We show that addition of CotA-laccase to PpAzoR reaction mixtures lead to a significant drop in the final toxicity. A sequential enzymatic process was validated through the use of 18 representative azo dyes and three model wastewaters that mimic real dye-containing effluents. A heterologous Escherichia coli strain was successfully constructed co-expressing the genes coding for both PpAzoR and CotA. Whole-cell assays of recombinant strain for the treatment of model dye wastewater resulted in decolourization levels above 80% and detoxification levels up to 50%. The high attributes of this strain, make it a promising candidate for the biological treatment of industrial dye containing effluents.
Copyright © 2011 Elsevier Ltd. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Azo Compounds / isolation & purification
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Azo Compounds / toxicity
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Bacillus subtilis / enzymology
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Bacillus subtilis / genetics
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Biodegradation, Environmental / drug effects
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Caenorhabditis elegans / drug effects
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Caenorhabditis elegans / physiology
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Color
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Coloring Agents / isolation & purification*
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Coloring Agents / toxicity
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Electrophoresis, Polyacrylamide Gel
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Escherichia coli / cytology
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Escherichia coli / drug effects
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Escherichia coli / metabolism
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Genes, Bacterial / genetics
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Inactivation, Metabolic
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Laccase / genetics
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Laccase / metabolism*
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Models, Chemical*
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NADH, NADPH Oxidoreductases / genetics
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NADH, NADPH Oxidoreductases / metabolism*
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Nitroreductases
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Oxidation-Reduction / drug effects
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Pseudomonas putida / enzymology
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Pseudomonas putida / genetics
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Reproduction / drug effects
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Saccharomyces cerevisiae / drug effects
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Saccharomyces cerevisiae / growth & development
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Toxicity Tests
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Waste Disposal, Fluid*
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Water Purification / methods*
Substances
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Azo Compounds
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Coloring Agents
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Laccase
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NADH, NADPH Oxidoreductases
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Nitroreductases
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azoreductase