Assessing the Tolerance Impact of Fungal Isolates against Lead and Zinc Heavy Metals under Controlled Conditions

Abstract

Now a day’s cultivated lands are being polluted with heavy metals which is become very common issue in the country as well as across the globe due to increase in geologic and anthropogenic activity. Because of human activity, there is excess release of heavy metals like cadmium, copper, lead, nickel, zinc, and/are going on increasing up to alarming level which may significantly affects the crop yield and soil micro flora as well. Reports revealed that biological treatments, especially filamentous fungi are playing an important role in removal of heavy metals from the contaminated environment of the ecosystem. Hence, in present study we have isolated filamentous fungi viz., Trichoderma spp. and Aspergillus niger from contaminated soil with heavy metals with aim to find their tolerance properties towards selective heavy metals such as, Lead and Zinc. Findings of our study highlighted that Trichoderma spp. have greater ability to grow under varying Zinc and Lead concentration and shows greater tolerance limit of 0.98 at 5mM of Zinc concentration and 0.83 tolerance limits at 100 ppm lead concentration. Similarly, the fungi Aspergillus niger has ability to grow faster at high lead concentration and shows tolerance limit of 1.07 at 200 ppm of lead concentration. Thus, it is concluded that the filament fungi namely Trichoderma spp. and Aspergillus niger are efficient in removal of toxic heavy metals from the polluted soil. Hence, we can employ these fungi individually or in consortium as effective agents for bioremediation of the contaminated soil in order to crop cultivation and enhancing the yield of useful crop plants for supplying the demand of growing population.