STTR Phase I: Microbially-Produced Precipitated Calcium Carbonates (mPCCs) as a Paint Filler

The broader/commercial impact of this Small Business Technology Transfer (STTR) Phase I project is the production of particulate calcium carbonates, which are an important filler used in paints, plastics, adhesives, and paper; products that play a crucial role in numerous industries, including construction and consumer goods. Traditional methods for producing high-quality particulate calcium carbonates are costly, energy-intensive processes that create supply chain risks and increase operational expenses for U.S. manufacturers. This project leverages a breakthrough biological process that produces high-quality calcium carbonates using bacteria, offering a reliable and cost-effective alternative to conventional manufacturing. This innovation has the potential to strengthen domestic production, reduce dependence on imported materials, and support industries that rely on these materials for high-performance products. By improving manufacturing efficiency and creating opportunities for new production hubs, our work promotes scientific progress and contributes to national prosperity. This research also opens pathways for advancements in microbial manufacturing, reinforcing the U.S. position as a leader in cutting-edge material science. The current global particulate calcium carbonate market is worth $14.5 billion, but this work will initially focus on high-value niche applications, such as cosmetics and water treatment. This Small Business Technology Transfer (STTR) Phase I project aims to scale a novel carbonate precipitation pathway in bacteria to produce industrially relevant precipitated calcium carbonates (PCCs). Micron-scale calcium carbonates have a number of industrial uses (in paper, thermoplastics, sealants and adhesives, and paints), providing a higher consistency in size, color, and chemistry, compared to cheaper alternatives. Nonetheless, traditional manufacturing processes are costly and relies on energy-intensive limestone sintering. This technology relies on cellular Ca²⁺ homeostasis in Escherichia coli, wherein the cell removes potentially toxic levels of Ca2+ via the production of precipitated calcium carbonates. The research will determine the scalability of production using this approach, while optimizing conditions to improve yield and product consistency. This will be accomplished by focusing on three key challenges: increasing production rates at bench (5 L) scale; examining techniques to improve the scalability of calcium carbonate recovery; and characterizing secondary, high value products (such as vaterite) formed during pre-aggregation phases. The obtained precipitated calcium carbonates will then be tested against commercially available products, to determine whether they meet or exceed industry standards. Anticipated results include the development of a scalable, cost-competitive alternative to sintered calcium carbonates that maintains the desired physical and chemical properties for use in paints and coatings. This research advances fundamental understanding of biomineralization processes while enabling a novel biotechnology approach with the potential to transform industrial precipitated calcium carbonate production. 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.