Fungal mediated decolorization of media containing procion dyes

Abstract

An isolated fungus, Aspergillus foetidus was found to effectively decolorize media containing azo reactive dyes, namely Procion dyes, under aerobic conditions. The extent of colour removal was 90% within 48 h of growth of the fungus. The entire colour was found to be strongly bioadsorbed to the rapidly settling spherical fungal biomass pellets. Our investigations reveal that the process of decolorization is concomitant with the exponential growth phase of the fungus and has an obligate requirement for a biodegradable substrate such as glucose. Kinetic analyses of fungal decolorization indicate that the rates of colour uptake decrease to a significant extent with increasing initial concentrations of dye. The fungus was able to grow and decolorize media in the presence of 5 ppm of chromium and 1% sodium chloride. An alternate and cheaper carbon source such as starch supported the growth and decolorization process. These results suggest that the dye uptake process mediated by Aspergillus foetidus has a potential for large-scale treatment of textile mill discharges.