Improvement of Soil Cohesion Using Microbial Activity

Abstract

Bio-cementation process or commonly known as MICP (Microbial Induced Calcite Precipitation) on soil is strongly influenced by urease enzyme activity. High of urease activity the precipitation of urea and calcium chloride into calcite particles will also increase. The urease enzyme is obtained from B.subtilis bacteria with isolate number P3BG41 and P3BG43. The bacteria was grown under B4 urine medium at 37 and pH+7 for five days observation. The B.subtilis was then daily measured its optical density and urease activity. The bacteria and combination of urea (CO(NH₂)₂) and calcium chloride (CaCl₂) were daily injected into the sand to obtain the optimum results from the calcite precipitation. The highest value of urease enzyme activity occurs on the second day incubation. While the optical density was reduced on the second day, the soil cohesion reaches the highest value at that day. However, the friction angle value on the second day has the lowest point compared to the other day.