Investigation on mineralization performance and spore germination conditions of calcium carbonate mineralizing bacteria

Abstract

Microbial induced calcium carbonate precipitation (MICP) provides a theoretical basis for repairing underground rocks. The optimal germination conditions and mineralization activities of Bacillus pasteurii with crack repair function were investigated. The growth and mineralization properties of microorganisms in different environments were explored by measuring the urease activity and calcium carbonate production of bacteria, and the influencing factors of bacterial biomass and urease activity were analyzed. The microscopic morphology of bacterial mineralization products was analyzed by SEM, XRD and TG-DSC test. The influencing factors of spore germination rate were studied by measuring the OD value of spore germination. The results showed that under the conditions of pH 7.3, urea concentration 0.25-0.5 mol l-1, and calcium ion concentration 0.4-0.6 mol l-1, the mineralization activity of B. pasteurii was the strongest, and the generated mineralization product was a stable calcite crystal. The optimum concentration of germination agent and inorganic salt were 10 mmol l-1 and 200 mmol l-1, respectively.