Abstract :
Microorganisms play a significant role in bioremediation of heavy metal contaminated soil and wastewater. Microorganisms including fungi have been accounted to remove heavy metals from contaminated sites through bioaccumulation at low cost and in eco-friendly way. In this study, an attempt was, therefore, made to check a strain of Alternaria alternata, isolated from leaves of Cupressus torulosa D.Don located in Garhwal, Himalayan region, has been studied for tolerance to various heavy metals (copper, lead, silver and mercury) and for its capacities to uptake these metals. It was found that endophytic fungus is capable of surviving on high metal concentrations, apparently as a result of the natural selection of resistant cells. Fungal endophyte was identified as Alternaria alternata by morphotypic and genotypic study. A. alternata exhibited removal of varying amount of heavy metals with respect to Cu+2, Pb+2, Ag+, Hg+2. Tolerance ability of fungus to heavy metals was determined by cultivating on Potato dextrose agar at concentration ranging from 50-1400ppm. The tolerant growths were studied for removal of heavy metals from liquid media at concentration from 50-250ppm of Cu+2, Pb+2, Ag+, Hg+2. In this paper we discussed that A. alternata was most efficient in removal of varying amount of heavy metals with respect Cu+2, Pb+2, Ag+, Hg+2 which showed the maximum uptake of lead of 80% and the least uptake of Ag of 63.1% at 50 μg/mL concentration. This indicated the potential of these fungi as bioaccumulation for removal of heavy metals from wastewater and industrial place effluents containing higher concentration of heavy metals which makes them attractive potential candidates as bioremediation agents. The results of this investigation could provide a basis for applying the endophytic fungi for an environmentally friendly and economically feasible decontamination of pollutants. Finally, the results indicated that A. alternata could be a prospective candidate for bioremediation processes.
Keyword :
Bioaccumulation; bioremediation; Endophytic fungi; Heavy metals tolerance.