Efficacy of microbially induced calcite precipitation in soil with existence of local microorganisms

The practical application of Microbially Induced Calcium
Carbonate Precipitation (MICP) for engineering soil improvement
necessitates considering the involvement of indigenous soil
bacteria. This research investigates the impact of indigenous soil
bacteria on the efficacy of MICP in soils sampled from a historical
site in Lopburi Province, Thailand, treated with Lysinibacillus
Sphaericus strains EW-S2 (Thai) and LMG22257 (foreign).
Evaluation parameters include calcium carbonate content,
ultrasonic wave velocity, permeability, and unconfined
compressive strength. Results are compared with a previous
study utilizing soil from the same site but sampled in the
summer season (Sirisingumpai et al., 2022). Findings indicate that
indigenous soil bacteria, particularly the EW-S2 strain of
Lysinibacillus Sphaericus, promote calcium carbonate
precipitation, contrary to the findings of Sirisingumpai et al.
(2022) suggesting that indigenous soil bacteria inhibit MICP
activity. This suggests the necessity of considering synergistic
interactions between indigenous soil bacteria and MICP bacteria
for practical implementation of MICP technology.