Potential of different white rot fungi to decolourize textile azo dyes in the absence of external carbon source

Abstract

The decolourization of azo dyes by various white rot fungi was studied in the absence of an external carbon source. Although the decolourization abilities of strains used in this study are well documented, these strains have not been studied or compared for their decolourization abilities in the absence of an external carbon source. Decolourization of dyes was also studied in the presence of the external carbon source glucose. Daedalea flavida and Phanerochaete chrysosporium were able to decolourize the dyes in the absence of glucose. D. flavida exhibited a better ability to decolourize the dyes as compared with P. chrysosporium in the absence of glucose. Culture conditions were optimized to enhance the decolourization ability of D. flavida. Shaking of cultures inhibited the decolourization of Amaranth by D. flavida. The optimum culture conditions were 36°C and pH 5.5 for decolourization of Amaranth in a stationary culture condition. We achieved 99% decolourization of Amaranth in 5 days under optimum conditions in the presence of glucose. D. flavida also decolourized the Amaranth with equal efficiency in the absence of glucose. To the best of the authors’ knowledge, this is the first paper reporting the decolourization of dyes in the absence of an external carbon source by D. flavida.

Keywords:

• white rot fungi
• textile azo dyes
• carbon source
• decolourization
• waste treatment