Influence of local microorganisms on microbiologically induced calcite precipitation in soil

This research investigated the influence of local microorganisms on microbiologically induced calcite precipitation (MICP) in soils. Two microorganisms that have the potential to produce urease and the interconnection between the particles of the soil granules, including Lysinibacillus sphaericus (L. sphaericus) strains EW-S2 and LMG 22257. Two types of soils including: 1. soil sterilized by an autoclave and 2. natural soil were used in the study to compare the influence of or the collaboration between local microorganisms and L. sphaericus on the process of precipitating calcium carbonate in the soil. For the treatment, the mixture of bacterial culture and chemical solution containing microorganisms was retained in the soil samples for 12 hours per cycle with the total period of 18 days. Together with the strength and permeability, the microstructure and amount of calcium carbonate induced in the treated soil samples were then examined by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectrometer (EDS). From the tests, it was found that the local microorganisms decreased the efficiency microbiologically induced calcite precipitation in the soil.