Enzymatic degradation of Congo Red by turnip (Brassica rapa) peroxidase.

Afaf Ahmedi (1, 2) , Mahmoud Abouseoud (1) , Annabelle Couvert (3) , Abdeltif Amrane (3)

1 Laboratoire de Biomatériaux et Phénomènes de Transport
2 Laboratoire de Génie de la Réaction
3 ISCR - Institut des Sciences Chimiques de Rennes

The enzyme peroxidase is known for its capacity to remove phenolic compounds and aromatic amines from aqueous solutions and also to decolourize textile effluents. This study aims at evaluating the potential of a turnip (Brassica rapa) peroxidase (TP) preparation in the discolouration of textile azo dyes and effluents. An azo dye, Congo Red (CR), was used as a model pollutant for treatment by the enzyme. The effects of various operating conditions like pH value, temperature, initial dye and hydrogen peroxide concentrations, contact time, and enzyme concentration were evaluated. The optimal conditions for maximal colour removal were at pH 2.0, 40 degrees C, 50 mM hydrogen peroxide, 50 mg/l CR dye, and TP activity of 0.45 U/ml within 10 min of incubation time. Analysis of the by-products from the enzymatic treatment by UV-Vis and IR spectroscopy showed no residual compounds in the aqueous phase and a precipitate of polymeric nature.

Mots clés: Congo Red; Discolouration; Peroxidase

Domaines: Génie des procédés; Génie chimique; Chimie analytique; Ingénierie de l'environnement

Afaf Ahmedi, Mahmoud Abouseoud, Annabelle Couvert, Abdeltif Amrane. Enzymatic degradation of Congo Red by turnip (Brassica rapa) peroxidase.. Zeitschrift fur Naturforschung C, 2012, 67 (7-8), pp.429-36. ⟨hal-00865917⟩