Textile dyes decolourisation by white-rot fungus Fomes fomentarius

Abstract

This paper summarizes experimental results obtained during textile dyes decolorisation (Fast Black HS-02 and Derma 2RN) by white-rot fungus Fomes fomentarius. White-rot fungi produce extracellular ligninolytic enzymes for degradation of the complex substrates, such as wood polymers, laccases playing an important role in these processes. Thus, prior to decolorisation tests, laccase activity was assayed in different culture media, highest value of 51.3 U/l being obtained us- ing medium supplied with cellulose as a source of organic carbon and KNO3 as a source of nitrogen. After 168 h of reaction time, decolorisation effciencies of Black HS-02 and Derma 2RN dyes were ranged between 54.9 and 67.7%, and 57.6 and 61.1%, respectively, for the following initial dyes concentrations: 20, 40, 60, 80 and 100 mg/l. No inhibitory effect was noticed on the decolorisation efficiency by initial dyes concentrations. Dyes decolorisation efficiency was also analysed using crude enzymatic extract produced under solid-state fermentation conditions. In the case of Black HS-02 dye, maximum decolorisation efficiency was registered for 40 mg/l (1.75%), the lowest value being recorded for 100 mg/l (1.14%). Regarding Derma 2RN dye, decolorisation efficiency decreased continuously from 1.13 to 0.09% per unit of laccase activity simultaneously with the increase of the initial dye concentration.