Effect of Divalent Cations (Cu, Zn, Pb, Cd, and Sr) on Microbially Induced Calcium Carbonate Precipitation and Mineralogical Properties

Abstract

Microbially induced calcium carbonate precipitation (MICP) is a bio-geochemical process involving calcium carbonate precipitation and possible co-precipitation of other metals. The study investigated the extent to which a urease-positive bacterium, Sporosarcina pasteurii, can tolerate a range of metals (e.g., Cu, Zn, Pb, Cd, and Sr), and analyzed the role of calcium carbonate bioprecipitation in eliminating these divalent toxicants from aqueous solutions. The experiments using S. pasteurii were performed aerobically in growth media including urea, CaCl2 (30 mM) and different metals such Cu, Zn, Pb, and Cd (0.01 ∼ 1 mM), and Sr (1 ∼ 30 mM). Microbial growth and urea degradation led to an increase in pH and OD600, facilitating the precipitation of calcium carbonate. The metal types and concentrations contributed to the mineralogy of various calcium carbonates precipitated and differences in metal removal rates. Pb and Sr showed more than 99% removal efficiency, whereas Cu, Zn, and Cd showed a low removal efficiency of 30∼60% at a low concentration of 0.05 mM or less. Thus the removal efficiency of metal ions during MICP varied with the types and concentrations of divalent cations. The MICP in the presence of divalent metals also affected the mineralogical properties such as carbonate mineralogy, shape, and crystallinity.

Immobilization of heavy metals by microbially induced carbonate precipitation using hydrocarbon-degrading ureolytic bacteria

“…Conversely, the formation of brushite was associated with significantly lower heavy metal removal efficiency of those heavy metals. Recent reports demonstrated that divalent heavy metals can interact with MICP [ 23 , 47 ]. It also has been shown that heavy metals such as cadmium, cobalt, nickel, zinc may alter the calcite dissolution process [47] .…”

“…It also has been shown that heavy metals such as cadmium, cobalt, nickel, zinc may alter the calcite dissolution process [47] . The incorporation of these heavy metals results in inhibition or enhancement of the solubility of calcite, depending on the type of metals and their content [23] . The formation of chromium oxide (Cr 2 O 3 ) in the Pseudomonas aeruginosa (QD5 & QZ9) UM-Cr cultures were combined with 100% of removal efficiency.…”

“…Microorganisms can generate carbonate compounds (CO 3 2− ) that react with calcium ions (Ca 2+ ) to produce CaCO 3 precipitates through microbially carbonate-induced precipitation (MICP). Similarly, heavy metals with an ionic radius similar to Ca 2+ , such as Pb 2+ and Hg 2+ , can replace Ca 2+ ions and be incorporated into the CaCO 3 crystal lattice [23] . In this way, heavy metals can be immobilized in contaminated soils [ 24 , 25 ].…”

Biomineralization Induced by Cells of Sporosarcina pasteurii: Mechanisms, Applications and Challenges

“…Fortunately, a biomineralization reaction induced by S. pasteurii cells could provide sufficient CO 3 2− ions to integrate these metal cations into undissolving carbonate for easy removal (Figure 4D) [82]. Soils contaminated with strontium (Sr) or lead (Pb) were successfully removed by biomineralization of S. pasteurii cells with more than 99% efficiency [83]. Recently, multiple heavy metals, such as cadmium (Cd), zinc (Zn) and copper (Cu), were also reported to be eliminated from soils using biomineralization technology [84,85].…”

Testing the Capacity of Staphylococcus equorum for Calcium and Copper Removal through MICP Process

“…These values are insufficient to support a potential application in a mining operation, where the removal of metals should be significant to justify the investment. Reports have shown low copper removals at copper concentrations over 0.5 mM and, on the contrary, high copper removals at lower copper concentrations [28,46].…”