Investigation on synergetic strategy for the rejuvenation of Cr (VI) contaminated soil using biochar-immobilized bacteria and cyanobacteria consortia

The study highlights the potential of Bacillus spp. SSAU-2 in rejuvenating soil fertility and emphasizes the importance of microbe adsorption on activated biochar. The primary objective is to restructure the quality of Cr (VI)-contaminated soil through the strategic use of bacteria and cyanobacteria immobilized on biochar derived from rice straw. The synthesized activated charcoal is highly porous, and immobilization significantly boosts the bacteria's ability to remove Cr (VI) from the soil. This ability increased from a threshold value of 60 ppm Cr (VI) to 500 ppm Cr (VI), indicating its efficacy. The microbe demonstrated multi-heavy metal tolerance, surviving even in 1000 ppm heavy metal concentrations. Moreover, the study revealed increased phosphate solubilization (49%), conductivity (175%), and salinity (53%), demonstrating the microbe's efficiency in solubilizing metal salts in the soil. The study also focuses on the community behavior of the bacterium in the soil in which it was found that the SSAU-2 mingles quite efficiently with the soil. Scanning Electron Microscope images confirmed the effective colonization of microbes within the pores of activated charcoal. Thus study presents a novel approach for the effective remediation of Cr (VI)-contaminated soil through the application of Bacillus sp. SSAU-2 immobilized on biochar. The research explored the dual benefits of heavy metal removal and repurposing of agricultural waste through open burning.