Comparative performance evaluation of multi-metal resistant fungal strains for simultaneous removal of multiple hazardous metals

In the present study, five fungal strains viz., Aspergillus terreus AML02, Paecilomyces fumosoroseus 4099, Beauveria bassiana 4580, Aspergillus terreus PD-17,Aspergillusfumigatus PD-18, were screened for simultaneous multimetal removal. Highest metal tolerance index for each individual metal viz., Cd, Cr, Cu, Ni, Pb and Zn (500 mg/L) was recorded for A. fumigatus for the metals (Cd, 0.72; Cu, 0.72; Pb, 1.02; Zn, 0.94) followed by B. bassiana for the metals (Cd, 0.56; Cu, 0.14; Ni, 0.29; Zn, 0.85). Next, the strains were exposed to multiple metal mixture (Cd, Cr, Cu, Ni, Pb and Zn) of various concentrations (6, 12, 18,30 mg/L). Compared to other strains, B. bassiana and A. fumigatus had higher cube root growth (k) constants indicating their better adaptability to multi metal stress. After 72 h, multimetal accumulation potential of B. bassiana (26.94 +/- 0.07 mg/L) and A. fumigatus (27.59 +/- 0.09 mg/L) were higher than the other strains at initial multimetal concentration of 30 mg/L. However, considering the post treatment concentrations of individual metals in multimetal mixture (at all the tested concentrations), A. fumigatus demonstrated exceptional performance and could bring down the concentrations of Cd, Cu, Ni, Pb and Zn below the threshold level for irrigation prescribed by Food and Agriculture Organization (FAO). (C) 2016 Elsevier B.V. All rights reserved.