Diatom silicon biomineralization as an inspirational source of new approaches to silica production

The demand for new materials and products is still growing and the interest in naturally formed biopolymers and biominerals, such as chitin, calcium precipitates and silica is increasing. Photosynthesizing microalgae of the family Bacillariophyceae (diatoms) produce silica exoskeletons with a potential to be used in specific industrial or technological processes, they also are an excellent model in studies of silicon biomineralization. In contrast to geologically aged diatomaceous earth, the freshly prepared silica of cultured or harvested natural diatoms has been characterized insufficiently with respect to the properties (e.g. purity, specific surface area, porosity) required for technological and industrial application. In this contribution we summarize aspects of cellular processes that are involved in silicon biomineralization of diatoms and the current knowledge of the characterization of diatomaceous silica, following methods used for synthetically derived silica-based materials. (C) 1999 Elsevier Science B.V. All rights reserved.