Abstract
The concept of microbially induced calcite precipitation (MICP) is in vogue for quite some time; but a multitude of factors that would lead to optimal bacterial activity enabling real time application of the technique in various intended processes are yet to be standardized. This study is an attempt to elucidate some of these factors. The study was conducted in sand columns simulating standard cement mortar conditions of high pH at room temperature. Sporosarcina pasteurii ATCC6453 cultures in broths at variable cell counts of 1 × 103, 105, 107, and 109 ml−1 with 0.2M concentrations of urea and calcium chloride were poured onto sand columns in plastic sheet molds. After variable incubation period of 24, 48, 72, and 96 h, urease activity of the bacterium was assayed calorimetrically. Physical verification of calcite deposition was done with scanning electron microscopy (SEM) and X-ray diffraction (XRD) after 28 days of treatment. Urease activity escalated significantly with increasing cell count and incubation period. SEM and XRD examinations revealed remarkable deposition of calcite in the columns under treatment.