title: Studies on the laccase-mediated decolorization, kinetic, and microtoxicity of some synthetic azo dyes.
abstract: BACKGROUND
  Enzymatic elimination of synthetic dyes, one of the most environmentally hazardous chemicals, has gained a great interest during the two last decades. The present study was performed to evaluate the decolorization and detoxification potential of the purified laccase of Paraconiothyrium variabile in both non-assisted and hydroxybenzotriazole-aided form against six azo dyes.
  
  
  RESULTS
  The obtained results showed that Acid Orange 67, Disperse Yellow 79, Basic Yellow 28, Basic Red 18, Direct Yellow 107, and Direct Black 166 were decolorized up to 65.3, 53.3, 46.7, 40.7, 34, and 26.2 %, respectively, after 1 h treatment with laccase (0.5 U/mL). Addition of HBT up to 5 mM enhanced decolorization percent of all the investigated dyes. The results of kinetic study introduced the monoazo dye of Acid Orange 67 as the most suitable substrate for laccase with K m of 0.49 mM and V max of 189 mmol/min/mg. Evaluation the toxic effect of laccase-treated dye sample based on the growth inhibition of standard bacterial strains revealed decrease in toxicity of all applied dyes after treatment by laccase.
  
  
  CONCLUSIONS
  Application of the P. variabile laccase as biocatalyst efficiently decreased the toxicity of all studied synthetic azo dyes.
authors.affiliation: Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Forootanfar
authors.affiliation: Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran, 1417614411 Iran.
authors.forename: Shahla
authors.initials: S
authors.lastname: Rezaei
authors.affiliation: Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran, 1417614411 Iran.
authors.forename: Hamed
authors.initials: H
authors.lastname: Zeinvand-Lorestani
authors.affiliation: Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran, 1417614411 Iran.
authors.forename: Hamed
authors.initials: H
authors.lastname: Tahmasbi
authors.affiliation: Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran, 1417614411 Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Mogharabi
authors.affiliation: Department of Medicinal Chemistry, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Alieh
authors.initials: A
authors.lastname: Ameri
authors.affiliation: Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran, 1417614411 Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Faramarzi
keywords: Decolorization; Detoxification; Hydroxybenzotriazole; Laccase; Microtoxicity