Biodecolourization and biodetoxification of dye-containing wastewaters from leather dyeing by the native fungal strain Trametes villosa SCS-10

Abstract

The native fungal strain Trametes villosa SCS-10 was investigated for its ability to treat wastewaters from real dyeing of leather produced in pilot-scale. Four types of wastewater using different compositions and dyes (Acid Red 357 and Acid Orange 142) were produced and used in the assays. Three culture conditions were studied. The efficiency of the treatment was assessed in terms of biodecolourization, mycoremediation: reduction of chemical oxygen demand (COD), biological oxygen demand (BOD), total organic carbon (TOC) and biodetoxification. The treatment resulted in between 50–70% of biodecolourization and 40–60% of COD and TOC reduction of the raw wastewater without nutrient addition (N0). However, when wastewaters were supplemented with a high (N1) and a reduced (N0.5) nutrient supply, over 90% of biodecolourization and over 80% of COD and TOC reduction were achieved. The treatment N0.5 allowed the highest values of colour, TOC and COD reduction, which were related to the major peaks of laccase activity (1000–1300 UL−1). The ecotoxicity assays with Raphidocelis subcapitata and Vibrio fisheri demonstrated that the fungal treatment resulted in 50–70% of biodetoxification. The MTT assay revealed that the treated wastewaters did not present cytotoxic effects to the cell line V79. These promising results show that Trametes villosa is suitable for the treatment of wastewater from leather dyeing. Further studies are required to improve the applicability of selected fungal strains in the treatment of wastewater from the tannery industry.