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Enzymatic biotransformation of the azo dye Sudan Orange G with bacterial CotA-laccase

Paper ID Volume ID Publish Year Pages File Format Full-Text
24758 43535 2009 10 PDF Available
Title
Enzymatic biotransformation of the azo dye Sudan Orange G with bacterial CotA-laccase
Abstract

In the present study we show that recombinant bacterial CotA-laccase from Bacillus subtilis is able to decolourise, at alkaline pH and in the absence of redox mediators, a variety of structurally different synthetic dyes. The enzymatic biotransformation of the azo dye Sudan Orange G (SOG) was addressed in more detail following a multidisciplinary approach. Biotransformation proceeds in a broad span of temperatures (30–80 °C) and more than 98% of Sudan Orange G is decolourised within 7 h by using 1 U mL−1 of CotA-laccase at 37 °C. The bell-shape pH profile of the enzyme with an optimum at 8, is in agreement with the pH dependence of the dye oxidation imposed by its acid-basic behavior as measured by potentiometric and electrochemical experiments. Seven biotransformation products were identified using high-performance liquid chromatography and mass spectrometry and a mechanistic pathway for the azo dye conversion by CotA-laccase is proposed. The enzymatic oxidation of the Sudan Orange G results in the production of oligomers and, possibly polymers, through radical coupling reactions. A bioassay based on inhibitory effects over the growth of Saccharomyces cerevisiae shows that the enzymatic bioremediation process reduces 3-fold the toxicity of Sudan Orange G.

Keywords
Laccase; Synthetic dyes; Biotransformation; Toxicity; Decolourisation
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Enzymatic biotransformation of the azo dye Sudan Orange G with bacterial CotA-laccase
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 139, Issue 1, 1 January 2009, Pages 68–77
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us