Decolourization and detoxification of textile industry wastewater by the laccase-mediator system

Rim Khlifi, Lassad Belbahri, Stephen Woodward, Mariem Ellouz, Abdelhafidh Dhouib, Sami Sayadi, Tahar Mechichi

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128 Citations (Scopus)

Abstract

Decolourization and detoxification of a textile industry effluent by laccase from Trametes trogii in the presence and the absence of laccase mediators was investigated. Laccase alone was not able to decolourize the effluent efficiently even at the highest enzyme concentration tested: less than 10% decolourization was obtained with 9 U/mL reaction mixture. To enhance effluent decolourization, several potential laccase mediators were tested at concentrations ranging from 0 to 1 mM. Most potential mediators enhanced decolourization of the effluent, with 1-hydroxybenzotriazol (HBT) being the most effective. The effect of several physico-chemical parameters that could influence enzyme activity, such as pH, temperature and dye concentration was tested. Optimal decolourization occurred with 20% effluent at pH 5, a temperature of 50 degrees C, and in the presence of 1 mM HBT.

The toxicities of crude, laccase-HBT treated and laccase-acetosyringone treated effluent were evaluated using the Microtox assay. Only laccase-acetosyringone treated effluent was not toxic; crude and laccase-HBT treated effluent retained toxicity.

Original languageEnglish
Pages (from-to)802-808
Number of pages7
JournalJournal of Hazardous Materials
Volume175
Issue number1-3
Early online date30 Oct 2009
DOIs
Publication statusPublished - 15 Mar 2010

Keywords

  • laccase
  • textile industry
  • dye
  • wastewater
  • mediator
  • white-rot fungi
  • catalyzed decolorization
  • synthetic dyes
  • oxidation
  • effluent
  • degradation
  • wastewaters
  • versicolor
  • acids

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