Optimization of Culture Condition and Influence of Mediators on Degradation of Reactive Magenta-HB Dye Using Ganoderma cupreum AG-1

Reactive dyes are important chemical pollutants from the textile industries. Utilization of microbes including white rot fungi for decolorization of synthetic dyes is one promising strategy of an environmental friendly and cost-competitive alternative to physico-chemical decomposition processes for the treatment of industrial effluents. The present study investigates the biodegradation and decolorization of reactive dyes using white rot fungi Ganoderma cupreum AG-1. Physico-chemical parameters including carbon and nitrogen sources, initial glucose and yeast extract concentration, pH, temperature, initial dye concentration, along with the effect of various metal ions and mediators were studied for the decolorization of Reactive Magenta-HB dye. The fungal isolate efficiently decolorized Reactive Magenta HB within 48 h at 28°C, at pH 5.0 and under optimized conditions 94.20 ±1% dye decolorization was obtained within 48 h. The effect of mediators on laccase, manganese peroxidase (MnP) and manganese independent peroxidase (MnIP) were also studied. The decolorization of Reactive Magenta-HB dye was monitored by UV–Visible spectroscopy while dye degradation was studied by HPTLC and FTIR spectroscopy.

Spectrum of various textile dyes was studied to determine for maximum percent decolorization efficiency of Ganoderma cupreum AG-1, which showed maximum percent decolorization of Reactive Magenta-HB dye.

One single factorial design was adopted for the media optimization study of the decolorization of Reactive Magenta-HB dye.

Supplementation of metal ion (Ca²⁺) and mediator (veratryl alcohol) have shown positive influence upon decolorization efficiency.

Various ligninolytic enzyme activities were determined which showed an increase in activities with the supplementation of mediators like tyrosine and veratryl alcohol and 1.26 fold rise was observed in laccase activity in presence of Veratryl Alcohol.

Degradation analysis was done using FTIR and HPTLC techniques, change in the spectra of decolorized sample and different R_f value of different bands suggests structural transformations occurred in the dye structure due to biological treatment.