Decolorization and degradation of Indigo Carmine dye from aqueous solution catalyzed by horseradish peroxidase. (January 2014)

• Record Type: Journal Article
• Authors: Terres, Josias; Battisti, Rodrigo; Andreaus, Jürgen; de Jesus, Paulo Cesar
• Is Part Of: Biocatalysis and biotransformation. Volume 32:Number 1(2014)
• Page Start: 64
• Page End: 73
• Publication Date: 2014-01
• Subjects: Enzymes -- Biotechnology -- Periodicals; Enzymes -- Industrial applications -- Periodicals; Biotransformation (Metabolism) -- Periodicals; 660.63
• DOI: 10.3109/10242422.2013.873416
• Languages: English
• ISSNs: 1024-2422

Abstract

<abstract> <title>Abstract</title> <p>We have studied the kinetics of decolorization of aqueous solutions of the dye Indigo Carmine and its biocatalytic degradation by the enzyme horseradish peroxidase (HRP). Experiments were carried out with a dye concentration of 2.5 × 10<sup>−5</sup> mol L<sup>−1</sup> over a temperature range of 25–60°C and decolorization was monitored spectrophotometrically at 610 nm. Furthermore, the concentration of H<sub>2</sub>O<sub>2</sub> (30%, 3%, 0.3%, 0.03% and 0.003%), essential for enzyme activation, the pH (4, 5, 6, 7, and 8) and the amount of enzyme (1, 2, and 3 mg) were varied. In the kinetic studies, it was observed that the decolorization curves followed first-order kinetics, which were used to determine the rate constants which ranged from 10<sup>−2</sup> to 10<sup>−3</sup> min<sup>−1</sup>, proving this to be a fast process, with color disappearance between 30 and 60 min. Acid conditions pH (4, 5, and 6), temperatures between 40°C and 60°C and hydrogen peroxide concentration between 0.3% and 0.003% with 2 mg of HRP enzyme, favored decolorization. The kinetic parameters [activation energy (<italic>E</italic><sub>a</sub>), activation enthalpy (ΔH<sup>#</sup>), activation Gibbs energy (ΔG<sup>#</sup>), and activation entropy (ΔS<sup>#</sup>)] were determined using the Arrhenius and Eyring equations. The results obtained for the best experimental conditions were as follows: <italic>E</italic><sub>a</sub> = 15.6 kJ mol<sup>−1</sup>, ΔH<sup>#</sup> = 18.2 kJ mol<sup>−1</sup>, ΔG<sup>#</sup> = 7.3 kJ mol<sup>− 1</sup>, and ΔS<sup>#</sup> = 0.036 kJ mol<sup>−1</sup> K<sup>−1</sup>, with an efficiency of 99% of decolorization. Studies showed that HRP combined with H<sub>2</sub>O<sub>2</sub> is effective in the decolorization and degradation of the Indigo Carmine dye.</p> </abstract>