Phytoremediation of Heavy Metal- Contaminated Tailings Soil by Symbiotic Interaction of Cymbopogon Citratus and Solanum Torvum with Bacillus Cereus T1B3

Abstract

Environmental pollution by dumping of tailings and overburden from different industrial activities has become a critical issue due to considerable increase in heavy metals (HMs) in all compartments of environment, especially in soils. Phytoremediation shows potential for remediating mine tailing sites contaminated with HMs. The aim of the present study was to isolate, characterize, and assess the native potential HM-resistant bacteria to enhance growth and metal accumulation of Solanum torvum and Cymbopogon citratus. In this study, a pot experiment was conducted to evaluate the effect of native Bacillus cereus T1B3 strain, which can produce plant growth-promoting traits including 1-aminocyclopropane-1-carboxylate deaminase (ACC), Indole Acetic Acid (IAA), Siderophores production, Nitrogen fixation, and Phosphate solubilization on the growth and metal uptake of S. torvum and C. citratus growing in multi-metal-contaminated soil. Inoculating tailings with T1B3 strain significantly increased biomass, photosynthetic pigment content, enzymes and HMs (Cr (VI), Fe, Mn, Cu, Cd, Ni and Zn) accumulation in both plants. Based on translocation and biococentration factors, both plants acted as a potential phytostabilizer of HMs in roots. Results indicate that inoculating of native B. cereus T1B3 strain with S. torvum and C. citratus improves its efficiency for phytoremediation of soil containing mine tailings contaminated with HMs.