FMSG: Bio: Just Add Water and Cyanobacteria: Biomanufacturing Routes to Cement and Stabilized Soil

Concrete is the most widely used building material globally. Around 4.6 billion tons of cement is produced annually to meet growing urbanization, industrialization, and infrastructure demands. However, conventional Portland cement manufacturing is among the most energy intensive industries, primarily due to its high-temperature production process.

This Future Manufacturing Seed Grant (FMSG) research project explores a novel, lower-energy approach to cement manufacturing by combining biological and chemical processes that will leverage waterways’ massive capacity to hold onto the key components used in cement production. Photosynthetic microbes called cyanobacteria look to be harnessed to produce solid calcium carbonate, a key component of cement, using sunlight and minerals in water.

This microbially produced calcium carbonate plans to then be combined with sand and other materials for a promising alternative route to cement manufacturing. The success of the project will help enhance the competitiveness of US manufacturing and increase the availability of critically needed building materials, ultimately lowering the costs for production of new buildings for homeowners and businesses.

The biomineralization of calcium carbonate from water sources using cyanobacteria is currently challenging for manufacturing applications. In this research project, the natural microbial carbonate mineralization process looks to be applied and improved through modification of the producer organisms and by controlling external environments to generate key components for biocement.

Calcium carbonate production using microbes requires high carbonate concentrations in concert with elevated calcium levels and availability of chemical conditions that facilitate solid precipitation. Synechococcus elongatus cyanobacteria and other strains important to calcium carbonate formation look to be modified to enhance precipitation of calcium carbonate in the environment.

Delivery of calcium carbonate seeks to be improved by increasing nucleation processes that facilitate carbonate precipitation to overcome barriers to solids formation. In concert, manipulation of extracellular conditions through electrochemical adjustment of environmental pH intends to ensure maximum conversion of reactants to calcium carbonate precipitate.

Next, an integrated and scalable biocement manufacturing process that combines cyanobacterial growth and precipitation steps plans to be designed and implemented. A final goal will be to include biocement in infrastructure materials and test that these materials are mechanically stable and possess sufficient stiffness and strength. The project will include experts in microbial biomanufacturing, electrochemical engineering, and mechanical testing.

Further, this project looks to train future engineers from high school to graduate levels in key concepts including microbial fermentation, electrochemistry, and mechanical testing of materials, and demonstrate how these skills will be applied to design, develop, and implement the next wave of innovative, low-cost manufacturing processes.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.