(663f) Identifying the Genetic Mechanisms of Diatom Silicification for the Production of Novel Biomaterials

Biological systems present attractive alternatives for traditional industrial processes in the search for new and more environmentally friendly technologies. The production of silica-based materials is one such area for which biological processes exist that may be able to supplement, replace, or improve current manufacturing approaches. Specifically, the unicellular, eukaryotic algae know as diatoms are recognized for their ability to synthesize cell walls made almost entirely of hydrated silica at ambient temperatures and pressures. Additionally, these cell wall structures typically contain a high degree of intricate micro- and nano-scale patterning. As such, there is increasing interest in the biosynthetic potential of diatoms for producing advanced silica-based materials, with applications ranging from catalyst support to drug delivery to micro-optics.

However, the engineering of diatom-derived materials is in its infancy, in part due to an incomplete understanding of the mechanisms underpinning siliceous cell wall synthesis. To help address this lack of knowledge, we are beginning investigations into the genetics of diatom silicification, with the ultimate goal of more precisely controlling and engineering this process. Transcriptomic and comparative genomic approaches in both model and non-model diatoms will enable us to identify novel genes influencing the intracellular silica-deposition process that leads to cell wall formation. For example, analysis of the transcriptional response of diatoms to conditions of silica-deprivation, as well as other nutrient stresses, is guiding our identification of genes regulating morphological stress responses, such as loss of spines or pores in the cell wall. Likewise, transcriptional analysis of diatom resting spore formation, in which the silica morphology drastically alters, will help to reveal the genes governing this change. The combination of these ‘omics approaches with morphometric and materials-characterization techniques (e.g. sold-state NMR) will additionally allow us to identify relationships between diatom genes and the material properties of the cell-wall. Lastly, a small but growing set of genetic tools for use in diatoms enables us to directly probe candidate silica-associated genes to assess their role in cell wall formation. Through these and other approaches we are working to reveal genetic targets and control mechanisms to engineer diatom silicification for the production of advanced biomaterials.