Currently, agricultural land in most nations is threatened by heavy metal contamination, which could affect agricultural practices. This study screens out potential isolates from the consortia of microbiota recovered from the heavy metal-contaminated soil samples. The bacterial isolate was characterized and analyzed for its impending ability to tolerate heavy metals, chromium reduction, biosorption, and plant growth-promoting activities. The 16S rRNA gene sequencing method was used to identify the bacterial isolate. The phylogenetic analysis of accession number HE681416.1 confirmed that the approved isolate had a 99% chance of being Sinorhizobium saheli. Bacterial isolate was reduced and accumulated 91% chromium (Cr) and tolerated up to 1000 µgmL⁻¹ of nickel (Ni) and 250 µgmL⁻¹ of cadmium (Cd). Freundlich and Langmuir adsorption constants for heavy metal biosorption were calculated from isotherm. A correlation coefficient (r² > 0.98) with a maximum of 96.24% copper (Cu) accumulation was found and followed the order with other metals as: Cu > Cr > Ni > Cd > Pb > Zn. Additionally, isolate significantly solubilized phosphate up to 285 ± 7 µgmL⁻¹, produced indole acetic acid (IAA) up to 30.5 ± 1.9 µgmL⁻¹ and siderophore (25.0 ± 1.5 µgmL⁻¹). These findings revealed that microbial isolate was excellent metal tolerant and plant growth-enhancing traits in metal stress condition. It might be a significant bioinoculant for soil fertility restoration and crop development in metal-stressed real-field conditions.

Graphical Abstract