Synthetic dyes biodegradation by fungal ligninolytic enzymes: Process optimization, metabolites evaluation and toxicity assessment


Jazel Doménica Sosa-Martínez1, Nagamani Balagurusamy2, Julio Montañez1, Rosely Aparecida Peralta3, Regina de Fátima Peralta Muniz Moreira4, Adelar Bracht5, Rosane Marina Peralta5, Lourdes Morales-Oyervides1*

1Department of Chemical Engineering, Faculty of Chemical Sciences, Autonomous University of Coahuila, Boulevard Venustiano Carranza SN, Saltillo, Coahuila, 25280, Mexico

2Bioremediation Laboratory, Faculty of Biological Sciences, Autonomous University of Coahuila, LibramientoTorreón-Matamoros, Torreón, Coahuila, 27000, Mexico

3Department of Chemistry, Federal University of Santa Catarina, Brazil

4Department of Chemical Engineering, Federal University of Santa Catarina, Brazil

5Department of Biochemistry, State University of Maringá, Avenue Colombo 5790, Maringá, Paraná, 87020, Brazil


This work aimed to provide information that contributes to establishing environmental-friendly methods for synthetic dyesdegradation. The potential decolorization capacity of the crude enzymatic extract produced by Phanerochaete chrysosporium CDBB 686 using corncob as a substrate was evaluated on seven different dyes. Critical variables affecting the in-vitro decolorization process were further evaluated and results were compared with an in-vivo decolorization system. Decolorization with enzymatic extracts presented advantages over the in-vivo system (higher or similar decolorization within a shorter period). Under improved in-vitro process conditions, the dyes with higher decolorization were: Congo red (41.84 %), Poly R-478 (56.86 %), Methyl green (69.79 %). Attempts were made to confirm the transformation of the dyes after the in-vitro process as well as to establish a molecular basis for interpreting changes in toxicity along with the degradation process. In-vitro degradation products of Methyl green presented a toxicity reduction compared with the original dye; however, increased toxicity was found for Congo red degradation products when compared with the original dyes. Thus, for future applications, it is crucial to evaluate the mechanisms of biodegradation of each target synthetic dye as well as the toxicity of the products obtained after enzymatic oxidation.

Synthetic dyes-fungal biodeg-Optimization