This research project seeks to create a scalable, green, continuous process for biomineralization of nanoparticles directly from aqueous solutions at room temperature and to create structured catalysts for automotive and other industrial applications. Biomineralization is the process by which biological systems produce inorganic minerals, which display nanostructured features that are otherwise difficult to achieve. Nanostructured minerals are essential components in a number of industrially-important processes and products, in which control over the particle size is key to performance. As one example, certain nanostructured minerals, such as ceria, are used in automobile emission control, to remove carbon monoxide and other environmentally harmful exhaust gases. Current industrial methods for nanostructured ceria production often require high temperatures, high pressures and toxic solvents, thus limiting their utility. This research project involves studying methods to overcome these limitations by engineering enzymes as biocatalysts for the large-scale production of nanostructured ceria. The researchers on this project collaborate with researchers at Cerion, an industrial partner, to understand industrial-scale production issues. This project provides a unique, cross-disciplinary educational opportunity for U.S. graduate and undergraduate students to gain training in synthetic biology, nanoparticle manufacturing and catalysis. It also provides opportunities to partner with leading international institutes such as the Cardiff Catalysis Institute which will enable U.S. students to learn state-of-the-art production and characterization methods. This project will lead to a new, environmentally-friendly process to produce high-value materials and demonstrate their enhanced performance in consumer products such as automobiles.
The goal of this research is to develop a robust, green and flexible platform for the high-yield enzymatic synthesis of size-controlled ceria and ceria-zirconia nanoparticles directly from aqueous solutions at room temperature, and to integrate these materials into structured catalyst platforms. The approach is to study and develop engineered silicatein, the enzyme responsible for silica mineralization in sea sponges, to control mineralization of both ceria and ceria-zirconia in a size range, less than 2 nm, that enables functional superiority in primary catalytic applications as compared to conventional chemically-synthesized nanoceria. The fundamental technical barriers to scalable, green nanomanufacturing of these materials are overcome by using directed evolution in engineering enzymes with enhanced nanoceria synthesis rates and integrating them into immobilized enzyme biocatalysts for large-scale nanoceria production. The unique advantages of biomineralization enables the synthesis of smaller, more homogeneous nanoparticles and the direct, enzymatic synthesis of nanomaterials on structured support materials for their integration into catalytic nanosystems. Ultimately, the ability to produce nanoceria directly from aqueous solutions and to control particle size will create the next generation of these important classes of new, emergent nanomaterials at a cost and scale compatible with the needs of industry.
