Mitigation of the liquefaction potential of soil by Ca-carbonate precipitation induced by indigenous urease-producing Staphylococcus sp. IR-103
- 32 Downloads
Biocementation is a microbially induced technology that increases the shear strength of soil through the production of soil particle-binding materials known as calcite (calcium carbonate). This process makes use of urease-positive microorganisms, urea and calcium ions. The main aim of this study was to introduce an indigenous soil bacterium belonging to the genus Staphylococcus that was capable of hydrolyzing urea and precipitating calcium carbonate (CaCO3). Molecular identification of this isolate by 16S rDNA sequencing showed 98% homology to Staphylococcus sp. Several culture media were employed to investigate the growth, urease production and CaCO3 precipitation of this strain (designated Staphylococcus sp. IR-103, accession number LT853888). When Staphylococcus sp. IR-103 was grown in YN medium containing 20 g L−1 of yeast extract and 10 g L−1 of NH4Cl, maximal growth yield (OD600), urease activity and carbonate precipitation values of 2.8 ± 0.1, 3.33 ± 0.12 IU and 47.6 ± 0.9 mg mL−1 were obtained, respectively. The precipitated CaCO3 was characterized by FTIR, AAS, XRD and SEM analyses. In order to study the effects of the bacterium’s biocementation activities on soil strength, bacterial suspension and cementation solution was injected into a column packed with uniform sandy soil under defined condition. In conclusion, Staphylococcus sp. IR-103 is a high urease producer, which can grow on a simple and cost-effective medium without staying viable for long following the biocementation process. Hence this newly isolated strain has the potential to be employed in soil improvement for large-scale field applications.
KeywordsBiocementation Calcite precipitation Soil improvement Sporosarcina pasteurii Staphylococcus sp. Urease
This work was financially supported by a research Grant from the National Institute of Genetic Engineering and Biotechnology (NIGEB Project #103), which is greatly appreciated. We also thank Dr. Shariati for her great help.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Al-Thawadi SM (2013) Consolidation of sand particles by aggregates of calcite nanoparticles synthesized by ureolytic bacteria under non-sterile conditions. J Chem Sci Technol 2:141–146Google Scholar
- Holt JG, Krieg NR, Sneath PHA, Staley JT, Williams ST (1994) Bergey’s manual of determinative bacteriology, 9th edn. Lippincott Williams and Wilkins Publisher, BaltimoreGoogle Scholar
- Kucharski ES, Cord-Ruwisch R, Whiffin V, Al-Thawadi SMJ (2006) Microbial biocementation. World Intellectual Property Organization, WO2006/066326 A1Google Scholar
- Macegoniuk K (2013) Inhibitors of bacterial and plants urease. Folia Biol Oecol 9:9–16Google Scholar
- Mobley HL, Island MD, Hausinger RP (1995) Molecular biology of microbial ureases. Microbiol Rev 59:451–480Google Scholar
- Ramachandran SK, Ramakrishnan V, Bang SS (2001) Remediation of concrete using micro-organisms. ACI Mater J Am Concr Inst 98:3–9Google Scholar
- Ramakrishnan V, Panchalan RK, Bang SS (2001) Improvement of concrete durability by bacterial mineral precipitation. In: 11th international conference on fracture, Turin, ItalyGoogle Scholar
- Saxena SK, Lastrico RM (1978) Static properties of lightly cemented sand. J Geotechn Geoenviron Eng 104 (ASCE 14259)Google Scholar
- Whiffin VS (2004) Microbial CaCO3 precipitation for the production of biocement. Dissertation, Murdoch University, AustraliaGoogle Scholar