Biomineralization of Carbonate by Terrabacter Tumescens for Heavy Metal Removal and Biogrouting Applications

Abstract

The ability of Terrabacter tumescens to precipitate carbonate minerals has been demonstrated for the first time. Biomineralization of nickel, copper, lead, cobalt, zinc, cadmium and calcium by T. tumescens and mineral precipitations in both liquid and porous media were investigated. T. tumescens produced the enzyme urease which can hydrolyze urea. Due to this enzymatic reaction, soil pH increased and carbonate was produced, which results in mineralization of the soluble heavy metal ions present in soil water and their ultimate conversion to carbonates. And we studied the process of calcium carbonate precipitation induced by T. tumescens in sand column. The precipitated minerals were studied by scanning electron microscopy and X-ray diffraction, bioaccumulated divalent metal cation were deposited around the cell envelope as rhombohedral, sphere and needle shaped crystalline carbonate compounds. T. tumescens can play important role in heavy metal bioremediation and increase the strength and stiffness of sand and stone in civil engineering applications.