Fungal mechanisms of textile dyes biodegradation

Abstract

Reactive dyes are widely used in the textile industry. Coloured effluents from dyestuff and textile industries. the major producers and users of azo dyes. not only produce visual pollution but con also be detrimental to life. as they ore usually resistant to biological treatment. Additionally. fungi, mainly white rot fungi. have shown the ability to degrade numerous aromatic organopollutants. including textile dyes. via oxidative mechanisms till their complete mineralisation. avoiding the formation of anilines as intermediates. In our work. textile azo dyes were synthesized using aminobenzoic and ominosulphonic acids as diozo components and bioaccessible groups such as 2-methoxyphenol (guaiocol) and 2,6-dimethoxyphenol (syringol) as coupling components. The bioaccessible groups are present in the lignln structure and seem to be access points to the ligninolytic enzymes produced by white rot fungi. The fungal biodegrodation of the ozo dyes were studied in order to establish the relationship between the chemical structure of the dye and the extent of biodegrodation. The rule of the non-specific fungal ligninolytic enzymatic system, lignin peroxidoses. manganese peroxidases and loccoses. as well as the enzyme glyoxal oxidose wich produce H202 for the activities of both peroxidoses were studied. Reactive Black 5 and the anthraquinone-bosed polymeric dye Poly R-478 hove been currently used to screen the fungal biodegradation under alkaline conditions (pH ≥ 8.0). In order to adapt the fungi to this alkaline condition a chemostat is now used. To perform this work the fungi used were supplied by the culture collection Micoteca do Universidade do Minho (MUM).