Nonclassical Crystallization of Variable Valency Metal in the Biomineralization Process

In nature, microorganisms can coexist and interact with various metals and their metallic compounds, ultimately affecting their migration rate, circulation process, and distribution state in the environment, which confirms that they can participate in every step of the metal geochemical cycle. As the most active and powerful geological force in the earth's surface biosphere, the biological action will inevitably have a great influence on the formation and transformation of sedimentary lithosphere minerals. Of which, biomineralization refers to the process by which living forms influence the precipitation of minerals. The microorganisms concentrate aqueous dissolved metals onto cell walls and at intracellular sites during the life cycle and strongly bind metals during early diagenesis. For this process, nonclassical crystals are disequilibrium assemblages, which are created and maintained during life by dynamic metabolism. The biomineralization can be interpreted as an important medium for microbial- mineral-environmental interactions. This chapter mainly reviews nonclassical crystallization behaviors occurring in the biomineralization processes of variable valency cations (As, Cr, Fe, Mn, and U). The nonclassical crystallization behaviors of variable valency cations (As, Cr, Fe, and Mn) for biomineralization and the nonclassical crystallization behaviors in the biomineralization processes with U by plants and microbes are discussed.