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Enzyme Research
Volume 2015, Article ID 575618, 9 pages
Research Article

Effect of Diffusion on Discoloration of Congo Red by Alginate Entrapped Turnip (Brassica rapa) Peroxidase

1Laboratoire de Biomatéraiux et Phénomènes de Transport, Faculté des Sciences et de la Technologie, Université de Médéa, Pole Universitaire, RN1, 26000 Médéa, Algeria
2Laboratoire de Génie de la Réaction, Faculté de Génie Mécanique et Génie des Procédés, Université Houari Boumediene, 16111 Bab Ezzouar, Algeria
3Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, avenue du Général Leclerc, CS 50837, 35708 Rennes Cedex 7, France
4Université européenne de Bretagne, 35000 Rennes, France

Received 23 September 2014; Revised 16 January 2015; Accepted 20 January 2015

Academic Editor: Jose M. Guisan

Copyright © 2015 Afaf Ahmedi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Enzymatic discoloration of the diazo dye, Congo red (CR), by immobilized plant peroxidase from turnip “Brassica rapa” is investigated. Partially purified turnip peroxidase (TP) was immobilized by entrapment in spherical particles of calcium alginate and was assayed for the discoloration of aqueous CR solution. Experimental data revealed that pH, reaction time, temperature, colorant, and H2O2 concentration play a significant role in dye degradation. Maximum CR removal was found at pH 2.0, constant temperature of 40°C in the presence of 10 mM H2O2, and 180 mg/L of CR. More than 94% of CR was removed by alginate immobilized TP after 1 h of incubation in a batch process under optimal conditions. About 74% removal efficiency was retained after four recycles. Diffusional limitations in alginate beads such as effectiveness factor η, Thiele modulus , and effective diffusion coefficients (De) of Congo red were predicted assuming a first-order biodegradation kinetic. Results showed that intraparticle diffusion resistance has a significant effect on the CR biodegradation rate.