Screening of Nickel- Tolerant Microfungi for Bioremediation

Soil samples were screened for fungi tolerant to nickel (nickel chloride) using poisoned food technique. Control media as well as media supplemented with 40ppm, 200ppm and 400ppm concentrations of nickel (in the form of nickel chloride) were used to isolate fungi by serial dilution plate method. In total, 15 species of fungi were isolated. Out of these, two species, i.e. Trichoderma glaucum E.V. Abott and an ascomycetous strain could tolerate the highest concentration (i.e. 400ppm) of nickel. In addition to the above two fungal strains, Aspergillus niger var. niger Tiegh, and Trichoderma lignorum var. lignorum (Tode) Harz, could tolerate and grow well on the media with moderate concentrations (200 ppm) of nickel chloride. Aspergillus versicolor var. versicolor (Vuill.)Tirab., Verticillium effusum G.H. Otth and Verticillium glaucum Bonord are moderately resistant as these could grow and flourish at 40 ppm concentration only. Scopulariopsis communis var. communis Svilv., Fusarium moniliforme var. moniliforme J. Sheld, Cephalosporium coremoides and Penicillium implicatum var. implicatum Biourge cannot tolerate even low doses of nickel nitrate. Out of these 15 species, 5 fungal species, i.e., Aspergillus fumigatus var. fumigatus Fresen, Aspergillus niger, Botryotrichum atrogriseum J.F.H. Beyma, Trichoderma glaucum and Trichoderma lignorum were selected for studying the effect of different concentrations of nickel chloride on the in vitro growth of individual species. Thus, these species can be further tried for their utilization as biosorbents for remediation of nickel in the effluents.