Efficient mycosorption of anionic azo dyes by Mucor circinelloides: Surface functional groups and removal mechanism study

Abstract

In this study, fungal isolates were purified from contaminated soil and dyestuff wastewater samples. Among 58 fungal isolates, Mucor circinelloides with 94% Congo red removal capacity at the concentration of 150 mg/L was selected as the superior isolate. Comparison of wet and dried wet biomass showed that dye adsorption of wet biomass was 39% more than that of dried wet biomass. The maximum Langmuir adsorption capacity was calculated 169.49 mg dye/g wet biomass of M. circinelloides. Pretreatment of biomass with sodium hydroxide enhanced dye removal for 19%. Acetone 50% and 0.1 M acetic acid had the highest and the less effect on desorption of dye molecules from fungal cells, respectively. Light and scanning microscopy imaging, Fourier transform infrared spectroscopy, pretreatment and zeta potential analysis indicated that dye removal was performed through biosorption process and hydroxyl and amine groups in the cell wall polymers have the main role in dye biosorption. M. circinelloides could produce crude chitin as 57% of its dry biomass. Chitin and chitosan in zygomyceta cell wall such as Mucor genus are probably main adsorption contributing surface polymers.