Heavy metal accumulation from coal fly ash by cyanobacterial biofertilizers

Abstract

ABSTRACTBioleaching of heavy metals (Cu, Zn, Cr and Pb) from coal fly ash by cyanobacterial strains (Nostoc muscorum, Anabaena variabilis, Tolypothrix tenuis and Aulosira fertilissimia), that are commonly used as biofertilizers in rice cultivation was studied to assess utilization of fly ash while mitigating its environmental metal toxicity. Cyanobacteria were grown at different concentration of fly ash at 0, 5, 10, and 20% was treated with different blue green algal strains (Nostoc muscorum, Anabaena variabilis, Tolypothrix tenuis, and Aulosira fertilissimia) in suitable growth medium (BG-11) and distilled water to observe their growth and metal accumulation. Nostoc muscorum (ARM 442 mg g−1) showed maximum uptake of Cr (3.65 mg g−1), Pb (2.12 mg g−1) at BG 11(-N) medium amended with 10% fly ash, respectively. Anabaena variabilis (ARM 441) showed maximum uptake of Cu (0.313 mg g−1) and Pb (2.01 mg g−1) in BG 11 (–N) medium amended with 5% fly ash whereas Cr uptake (1.21 mg g−1) at 10% fly ash and Zn uptake (0.697 mg g−1) at 20% fly ash grown in BG 11(-N) medium. Increased accumulation of metals in blue green algae biomass grown in BG 11(-N) medium amended fly ash confirms that metal concentration was balanced between the algal strains.