ABSTRACT
Large amounts of chemical dyes are used for different industrial applications such as textile and printing industries. It is estimated that between 10 and 20 percent of about 0.7 million tons of dyestuff that are manufactured each year and used in dyeing processes may be found in wasterwater (Soares et al. 2001, Arantes et al. 2006). Several of these dyes are very conducive to light, temperature and microbial attack, making them recalcitrant compounds (Nyanhongo et al. 2002). Dyes can obstruct the passage of sunlight through water resources, leading to decreased photosynthesis by aquatic
Laboratory of Biochemistry of Microorganisms, State University of Maringá, PR, Brazil. *Corresponding author: E-mail: rmperalta@uem.br; rosanemperalta@gmail.com
plants coupled to a decreased concentration of dissolved oxygen, and to a diminished biodegradation of organic matters. Currently the removal of dyes from the effl uents is brought about by physicochemical means, including adsorption, precipitation, coagulation-fl occulation, oxidation, fi ltration and photo-degradation (Vandevivere et al. 1998, Ahn et al. 1999, Robinson et al. 2001). At the present, the biotechnological approaches have proven to be potentially effective and ecoeffi cient in the treatment of these pollution sources. Several microorganisms including bacteria, algae, yeast and fi lamentous fungi have the ability to decolorize and degrade a wide range of dyes (Forgacs et al. 2004, Pandey et al. 2007, El-Sheekh et al. 2009, Kaushik and Malik 2009). The possibility of using fi lamentous fungi associated with the decay of wood, usually called white-rot fungi, has attracted considerable attention. White-rot fungi possess a group of oxidative enzymes called lignin-modifying enzymes or ligninolytic enzymes involved in lignin degradation, mainly laccases and peroxidases. Due to the fact that ligninolytic enzymes are non-specifi c, they are able to attack a series of molecules chemically similar to lignin including pesticides, polyclyclic aromatic hydrocabons, synthetic polymers and synthetic dyes (Asgher et al. 2008).
