Induced phytoremediation of metals from fly ash mediated by plant growth promoting rhizobacteria.

ABSTRACT

A study was carried out to observe the impact of a consortium of bacteria isolated from the fly ash on the metal accumulation by T. latifolia. When a consortium of bacteria Bacillus endophyticus NBRFT4 (MTCC 9021), Paenibacillus macerans NBRFT5 (MTCC 8912) and Bacillus pumilus NBRFT9 (MTCC 8913) was bioaugmented into the rhizosphere of T. latifolia, it enhanced the metal concentration in root, stem and leaves of the plants through increased bioavailability of metals Fe, Cd, Pb, Cr, Ni, Cu and Zn in the fly ash. Besides, these bacteria also promoted the plant growth perhaps due to utilization of ACC, synthesis of phytoharmones and solubilisation of essential metals found in fly ash. As compared to fly ash alone, the accumulation of Fe was maximally enhanced by 164%, 196%, and 251%, followed by Ni by 92%, 44% and 56%, Zn by 82%, 57% and 91%, Cu by 71%, 53% and 60%, Cr by 96%, 80% and 105 %, Pb by 119%, 87% and 140%, Cd by 80%, 109% and 115% in root, stem and leaves, respectively in fly ash with bacteria. Thus, an increased solubilisation of metals coupled with enhanced plant growth stimulated the phytoextraction of metals by T. latifolia from fly ash.