Comparison of Effects of Different Nutrients on Stimulating Indigenous Soil Bacteria for Biocementation

Microbiologically induced calcite precipitation (MICP) is a biogeochemical process in which calcite is precipitated within the soil environment due to microorganism activity. Because soil properties are highly influenced by the microorganism population, soil properties can be improved by stimulating microorganisms in the soil with suitable materials. In this research, we investigated the abilities of six different carbon or nitrogen sources (treatments) to stimulate native urease-producing bacteria. Different amounts of yeast extract, sugarcane molasses, sodium acetate, and glucose were used to stimulate indigenous bacterial growth. After 7, 15, and 21 days of treatment, direct shear (DS), unconfined compressive strength (UCS), permeability test results, calcite content, and scanning electron microscopy (SEM) images obtained using an instrument equipped with an energy dispersive X-ray spectroscope (EDX) were used to analyze the samples. The results indicate that yeast extract had the greatest effect on improving soil properties by stimulating indigenous soil bacteria.