Identification of heavy metals tolerant Brevundimonas sp. from rhizospheric zone of Saccharum munja L. and their efficacy in in-situ phytoremediation

Heavy metals phytoremediation from pulp and paper industry (PPI) sludge was conducted by employing root-associated Brevundimonas sp (PS-4 MN238722.1) in rhizospheric zone of Saccharum munja L. for its detoxification. The study was aimed to investigate the efficiency of Saccharum munja L. for the removal of heavy metals along with physico-chemical parameters through bacterial interactions. Physico-chemical examination of PPI sludge showed biochemical oxygen demand (8357 ± 94 mg kg-1), electrical conductivity (2264 ± 49 μmhoscm-1), total phenol (521 ± 24 mg kg-1), total dissolve solid (1547 ± 23 mg kg-1), total nitrogen (264 ± 2.13 mg kg-1), pH (8.2 ± 0.11), chemical oxygen demand (34756 ± 214 mg kg-1), color (2434 ± 45 Co-Pt), total suspended solid (76 ± 0.67 mg kg-1), sulphate (2462 ± 13 mg kg-1), chlorolignin (597 ± 13.01 mg kg-1), K+ (21.04 ± 0.26 mg kg-1), total solid (1740 ± 54 mg kg-1), phosphorous, Cl-, and Na+. Heavy metals, such as Fe followed by Zn, Mn, Cd, Cu, Ni, Pb, As, Cr and Hg were above the permissible limit. Root and shoot of Saccharum munja L. revealed highest concentrations of Cd followed by Mn, Ni, Fe, Zn, Cu, As, Cr, Hg, and Pb. Tested metals (Fe, Mn, Pb, Cd, Cr, Cu, Zn, Ni, As, and Hg) bioaccumulation and translocation factors were also revealed to be < 1 and >1, respectively, demonstrating that these plants have considerable absorption and translocation abilities. Plant growth-promoting activity, such as ligninolytic enzymes, hydrolytic enzymes, indole acetic acid, and siderophore production activity of Brevundimonas sp. (PS-4 MN238722.1) were also noted to be higher. These findings support the use of Brevundimonas sp (PS-4 MN238722.1) in combination with Saccharum munja L. plant as interdisciplinary management of industrial sludge at polluted areas for the prevention of soils near the industrial site.