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Biomineralization of Different Trace Metals by Using Ureolytic Bacteria Isolated from Soil


Ammar Imad Ali Kasra and Hatice Atacag Erkurt
Abstract

Microbially induced carbonate precipitation (MICP) is an alternative technique for ground improvement in terms of soil strengthening and stabilization and for bioremediation of polluted sites as well. Urease producing bacteria including gram-positive and negative species which were isolated from the soil of Cyprus International University garden and identified as Bacillus lentus, Bacillus anthracis, Staphylococcus epidermidis, Staphylococcus aureus, Mycobacterium avium, Acinetobactor boumanii and Pseudomonas sp. This bacterial consortium was used for biomineralization of Ni+3, Hg+2, Pb+2, Cd+2 and Zn+2 at different concentrations. Trace metal removal data fitted well to the first-order kinetic model. Scanning electron microscopy and X-ray diffraction analyses revealed that bio-accumulated trace metal ions were deposited in the form of crystalline carbonate with the trace metals when the pH increases above 8.00 as a result of immobilization of the soluble trace metal ions present in soil solution and their final conversion to carbonates. The selected bacteria showed higher removal efficiencies and rates as well in the presence of urea than in the absence of urea within 20 hours incubation period except for mercury which showed the highest toxicity against urease enzyme with lowest k value. This study proved that indigenous bacteria could survive in the presence of different trace metals. The toxicity of trace metals increases by increasing the trace metal concentrations. Bioaugmentation seems to be a reasonable solution for trace metal removal by isolating and acclimating bacteria to lower concentrations of trace metals.

Volume 12 | Issue 3

Pages: 370-377

DOI: 10.5373/JARDCS/V12I3/20201203