Generation of enhanced endospores for microbially induced calcium carbonate precipitation (MICCP) via thermal shock for concrete self-healing
Seyed Ali Rahmaninezhad, Mohammad Houshmand Khaneghahi, Amir Sadighi, Divya Kamireddi, Reva M. Street, Yaghoob Farnam, Caroline L. Schauer, Ahmad R. Najafi, Christopher M. Sales
Abstract
Endospores are desirable phenotypes in Microbially-Induced Calcium Carbonate Precipitation (MICCP) for their durability in challenging environments. This study investigates the impact of various endosporulation methods on endospore morphology and their subsequent performance under harsh conditions. Results revealed that the Thermal Shock (TS) method produced larger endospores, possibly due to multi-layer encasement. Notably, endosporulation and germination ratios, besides MICCP effectiveness, achieved via TS-produced endospores surpass that of the Carbon Starvation method, both in vitro and within a cement-paste setting under freeze and thaw cycling. This outcome underscores the pivotal role of utilizing TS-produced endospores for concrete self-healing, particularly in cold areas.