Phyto-remediation of chrome-VI of tannery effluent by Trichoderma species

The tannery effluent carrying hazardous Cr(VI) species due to the oxidation of Cr(III) species was found to pollute the soil and the ground water of Jajmau area of Kanpur city where a large number of tanneries are located. We have studied the phyto-remediation of Cr(VI). Biosorption of the chromium ion Cr(VI) onto the cell surface of Trichoderma fungal species in aerobic condition was investigated. Batch experiments were conducted with various initial concentrations of chromium ions to obtain the sorption capacity and isotherms. The results obtained at pH 5.5 of chromium solution were 97.39% reduction by non pathogenic species of Trichoderma. It was found that the sorption isotherms of fungi for Cr(VI) appeared to fit Freundlich models. The results of FT-IR analysis suggested that the chromium binding sites on the fungal cell surface were most likely carboxyl and amine groups. The fungal surfaces showed efficient biosorption for Chromium in Cr+6 oxidation state. Best results for sorption were obtained at 5.5–5.8 pH, at low or high pH values, Cr(VI) uptake was significantly reduced.

The study of biosorption showed significant chromium uptake by Trichoderma filamentous fungi almost 100% by this non pathogenic species i.e., 10 ppm on wet weight of the fungi. Since metal biosorption from solution was predominantly due to physico/chemical interactions between the biomass and metal in solution, morphological differences existing within biomass can greatly influence the biosorption process. The cellular structure of Trichoderma mainly contains polysaccharide which can make significant difference in metal uptake by this species. Thus this fungal species can be a good source of cost effective biosorbent through biotechnological development for removal of Cr(VI) from industrial effluents in a potential manner. Another very important aspect of this study is the future use of the fungal strain in biosorption of other heavy metal species coexisting in various industrial effluents.