Optimizing the Scale-Up Production of the Biocementing Bacterium Sporosarcina pasteurii

Cement is one of the most consumed materials globally, second only to water. The production and maintenance of cement is unsustainable, costly, and a major contributor to greenhouse gas emissions. As urbanization and cement consumption continue to increase, the need to identify a sustainable, comparable, and environmentally friendly alternative becomes increasingly evident. Biocement is a sustainable biomaterial with properties similar to traditional cement. This technology relies on the CaCO3 production resulting from the growth and enzymatic activity of Sporosarcina pasteurii, a bacterium known for its capability of microbially induced calcite precipitation (MICP). The process exploits urease enzymes to catalyze a reaction that produces the ideal basic environment for this alkaliphile to thrive and drive CaCO3 formation. While the process of biocementation is still in its genesis, optimization of biocementation begins with optimizing production of the bacteria responsible for this technology. Here, we propose the optimization of large scale industrial growth through the use of 10 liter bioreactors to serve as a transitional step. By implementing and modifying specific growth parameters, we are able to monitor specific idiosyncrasies of S. pasteurii to produce the largest biomass yields in the shortest time possible, all while maintaining cementation (MICP) efficacy. To curb toxic ammonia production, we decreased the urea concentration that was recommended in previous literature, resulting in a 90% reduction of the produced ammonia with nominal effects to growth rate or cementation efficacy. Even in the absence of urea, bacterial growth is robust, so long as the environment is basic (9.5 pH), with the only detriment being an increase in lag time. With these basic parameters in mind, we were able to evaluate growth in alternative media. These low cost production techniques will further provide the building blocks for this contemporary technology and pave the way for a green and economically feasible alternative construction material.