Microbially Mediated Transformation of Metal and Metal Oxide Nanoparticles

Engineered nanostructures have a central role in energy conservation strategies and economic growth. One of the most significant impacts of engineered nanostructures is for effecting heterogeneous catalysis as required for fuel transformation, energy storage, polymer production and chemical synthesis. Metal and metal oxide nanoparticles are often used. They possess high surface areas and the ability to selectively mediate chemical transformations. The size and composition of the particle affects performance and may similarly affect nanoparticle fate and transport in the environment. The transformation of such nanoparticle catalysts in the environment is likely to proceed through interactions with bacteria. Several bacterial species are well known to interact with nanoparticles. Nanoparticle production, nanoparticle toxicity, nanoparticle binding and incorporation with bacteria have all been observed. However, basic knowledge that would allow prediction of the probable interaction between an engineered nanoparticle and bacteria is virtually nonexistent. This proposal seeks to quantify and characterize interactions between engineered metal or metal oxide nanoparticles and selected microbial species. The effect of size and chemical composition of nanoparticles that are currently considered for various applications in chemical catalysis will be studied. The results of these studies will provide a basis for understanding how nanoparticle size and composition influence their interactions with microorganisms, and how microorganisms may alter the fate and transformation of engineered nanoparticles in the environment. This will lead to an increased understanding of the potential environmental impact of commonly used engineered nanoparticles. Ultimately, these studies can guide effective routes for disposal of engineered nanoparticles and potentially guide the development of "ecologically friendly catalysts".