The accumulated bauxite mine soil had an acidic pH of 5.52 ± 0.12 and more heavy metals such as Cr, Cd, Zn, and Pb, which can cause severe soil and water pollution to the nearby farmlands and water reservoirs. Hence, the work was designed to find the possibility of reclamation of bauxite mine soil through Crotalaria juncea with the amalgamation of native metal degrading bacterial isolates. Out of 15 bacterial cultures, only 2 isolates (B3 and B14) showed excellent metal tolerance (for up to 750 mg L-1), solubilizing (15.27-38.7 mg kg-1) (including phosphate: 47.4 ± 1.79%), and degrading potential (22.8 ± 0.89 to 31.5 ± 1.6%) than the others. These B3 and B14 isolates were recognized as B. borstelensis UTM105 (1432 bp) and B. borstelensis AK2 (1494 bp) through molecular characterization. These isolates have produced a metal stress response protein (205-43 KDa molecular weight protein) during metal stress conditions. The phytoremediation competence of C. juncea under the influence of these bacterial isolates was assessed with various treatment (I-IV) schemes. The treatment IV (C. juncea with two bacterial isolates) showed substantial physiological and biochemical results compared with the control and the other treatments. The phytoremediation competence of C. juncea was also effective in treatment IV than the others. It reduced and extracted a reasonable quantity of metals from the bauxite mine soil. The intact results accomplished that these native metals tolerant, solubilizing, and degrading bacterial isolates, could be used as optimistic bacterial candidates in combination with C. juncea for the effective reclamation of metal enriched bauxite mine soil.
Keywords: Bauxite mine soil; Bioremediation; C. juncea; Metals; Phytoremediation.
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