Optimization of sporulation and germination conditions of functional bacteria for concrete crack-healing and evaluation of their repair capacity

While microbial spore production and germination of bacteria have been widely studied for their applications in animal husbandry, aquatic products, medicine, and food, few studies have investigated their use for the crack-healing of concrete. To effectively heal the cracks in concrete, studies suggest that the rate of sporulation and the germination of bacteria should be sufficiently high. This study investigates the effects of different carbon sources, nitrogen sources, Mn2+ concentrations, and external culture conditions on the sporulation rate and analyzes the effects of the pH value, heat activation, germinants, various cations, and nutrients on the germination of spores. Bacillus cohnii (B. cohnii) is chosen as the bacterium to be mixed in concrete because of its alkalophilic nature. The mineralization activity of spores after germination and the crack-healing capacity of concrete are studied. The optimal culture medium and the optimum external conditions for spore production are obtained. The total ...