Horseradish Peroxidase and Hematin as Biocatalysts for Alizarin Degradation

SILVINA PIRILLO; FERNANDO S. EINSCHLAG; ELSA H. RUEDA; MARÍA LUJÁN FERREIRA

INDUSTRIAL & ENGINEERING CHEMICAL RESEARCH

AMER CHEMICAL SOC

Año: 2010 vol. 49 p. 6745 - 6752

0888-5885

Degradation of organic dyes from the textile industry is a matter of enormous environmental concern. The horseradish peroxidase enzyme is known for its capacity to remove phenolic compounds and aromatic amines from aqueous solutions and also to decolorize textile effluents. This study evaluates the potential of the both, enzyme horseradish peroxidase (HRP) and its biomimetic hematin, in the decolorization of alizarin. We describe an UV-visible study of alizarin elimination from aqueous solutions by polymerization using HRP or hematin as catalysts, hydrogen peroxide as oxidant, and HCl as coagulant. The effects of the initial dye concentrationand the temperature on the decolorization efficiencies, attained with each catalyst after 2 h of reaction time,are reported. Alizarin removal with HRP/H2O2 achieved the highest elimination level (88%) when the dye concentration was 50 mg/L. At the same dye concentration a degradation of 97% was obtained using hematinas biocatalyst. A comparative analysis of time-resolved spectra and dissolved oxygen profiles is presented.The oxygen profiles found for hematin/H2O2/alizarin and HRP/H2O2/alizarin systems are clearly different, pointing to oxygen consumption for hematin and oxygen production for peroxidase.