Stabilization effect and mechanism of heavy metals by microbial consortium of phosphate-solubilizing bacteria and urease-producing bacteria

The precipitation of heavy metals could be promoted effectively when soluble starch (10.2 g/L) was used as carbon source and urea (7.8 g/L) as nitrogen source. The stabilization rates for Cu, Zn, Cd, and Pb were 98.35, 99.78, 99.09, and 92.26%, respectively. The stabilization rates of the combined action of PSB and UPB were significantly higher than that of the two microorganisms alone. An in-depth analysis showed that the composite metals were precipitated as dense precipitate encased in carbonate and phosphate, and additionally could be stabilized in the form of biosorption. Finally, the stabilization mechanism of heavy metals based on biomineralization and biosorption is proposed. These findings provide new theoretical support for sustainable remediation and management strategies for composite heavy metal polluted areas.