Biochemically Induced Carbonate Precipitation in Aerobic and Anaerobic Environments by Sporosarcina pasteurii

Microbially induced calcium carbonate precipitation (MICP) at laboratory scale for modifying the geotechnical properties of soils has been extensively investigated. The successful implementation of MICP in the field encounters many biotic and abiotic challenges. The study aimed to comprehend the role of oxygen availability on the efficacy of MICP catalyzed by S. pasteurii microbe. For this purpose, microbial growth rate, its ureolytic activities and carbonate precipitation by S. pasteurii over aerated, anoxic and anaerobic conditions were studied. The growth rate, ureolytic activity and amount of mineral precipitated were found to be insignificant under anaerobic environment compared to the remaining exposure conditions, which signifies the importance of oxygen for successful implementation of MICP process. The limited ureolytic activities and a minute amount of precipitation observed under anaerobic system were primarily attributed to the enzymes, already produced during the aerobic culture. The rise in the pH during the MICP process was not only because of ureolytic activities but also due to the breakdown of complex proteins in the stationary growth phase. As a whole, the MICP process was significantly inhibited in the absence of oxygen, or without frequent injection of S. pasteurii.