Aplicacion De La Hemoglobina Bovina Como Descontaminante De Las Aguas Residuales

APPLICATION OF BOVINE METHEMOGLOBIN TO AROMATIC AMINES REMOVAL FROM WASTEWATER1 Jesús Moraleda Mendoza, Mª Teresa Pérez Prior, Mª Isabel González Sánchez y Edelmira Valero Ruiz* Universidad de Castilla-La Mancha*

Aromatic amines are generally identified as those chemical compounds having in their molecular structure one or more aromatic rings, bearing one or more amino substituents (Pinheiroet al., 2004). Aromatic amines are presented in wastewaters as pollutants from chemical industry. Major sources of amines in the environment include several chemical industry sectors such as oil refining, synthetic polymers, dyes, adhesives and rubbers, pharmaceuticals, pesticides and explosives (Voyksner et al., 1993; Kataoka, 1996). These chemicals have been classified as priority pollutants byUS Environmental Protection Agency (EPA), and their use is extensively regulated (EPA Methods, 1994). This is due to these compounds are highly toxic and they are causing agents for multiples diseases worldwide, including cancer development in humans (Pinheiro et al., 2004). Given the increasing use of aromatic amines in various industries, control of their levels in environmental waters is ofcritical importance to the protection of human health and the environment. This has increased the demand for the development of simple, reliable, low cost and rapid removal methods in an environmental friendly way. Current methods for removing aromatic compounds from wastewater include microbial degradation, adsorption on activated carbon, chemical oxidation (using such agents as ozone, hydrogenperoxide or chlorine dioxide), incineration methods, solvent extraction and irradiation (Carvalho et al., 2006). However, these methods present certain disadvantages, such as low efficiency, high cost or generation of products that are more toxic than the original compound. As alternative way, enzymes represent one means by which selective removal of pollutants might be accomplished in waste treatment(Aitken, 1993). Enzymatic catalysis for the removal of aromatic compounds (bioremediation processes) has many advantages over more conventional methods; these advantages include a high degree of specificity, mild operating conditions, high reaction rates, which reduce processing costs, and the ability to catalyse in a wide range of pH and substrate concentrations (Choi et al., 1999). Among theenzymes which are able to remove these pollutants from wastewater are included horseradish peroxidase (HRP) (Klibanov et al., 1983; Vojinovic et al., 2007), soybean peroxidase (SBP) (Murcia et al., 2009), polyphenol oxidase (Fiessinger et al., 1984; Parveen et al., 2010) or laccase (Li et al., 2009). Nevertheless, these enzymes do not appear to be ideal catalysts for this kind of process because oftheir high cost. In contrast, hemoglobin (Hb), which also has peroxidase activity, is an abundant and cheap protein (Keilin and Hartree, 1955) that can be used for this purpose. Hemoglobin is the major heme protein of red blood cells and is responsible for the transport of oxygen to the tissues. Depending on the iron atom oxidation state, different forms of hemoglobin can be found, notably oxy-,deoxy- and met-hemoglobin. Met-hemoglobin (metHb), produced in vivo through an autoxidation process, is characterized by a ferric (Hb-FeIII) state of the hemin and
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Trabajo de Fin de Grado en Ingeniería Mecánica, dirigido por las profesoras Mª Teresa Pérez Prior y Edelmira Valero Ruiz, en el curso 2011/2012, actualmente en fase de realización. ISBN: 978-84-8427-859-7 INVESGRADO 2012

isunable to bind oxygen. Despite its principle role as an oxygen-carrier, Hb possesses different enzymatic activities, such as pseudo-peroxidase and pseudo-catalase activities due to its close structural similarity to peroxidase (González-Sánchez et al., 2009, 2011). This protein has been reported as able to catalyze the oxidation of numerous chemicals including arylamines, phenols, polycyclic...