ANALYZING THE MOLECULAR MECHANISMS FOR THE ASSEMBLY OF FUNCTIONAL MINERAL SCAFFOLDS WITHIN MICROBIAL BIOFILMS

The term bio-mineralization refers to minerals produced by organisms, most of these mineralized products are composite materials comprising of both mineral and organic components. We recently reported that structured calcite deposits produced by Bacillus subtilis provide resistance to environmental insults, as well as an efficient strategy for carbon dioxide sequestration and to increase the overall fitness of the community.

We used an unbiased approach to better understand the molecular events involved in biomineralization and performed RNAseq analysis of the transcriptome of the biofilm cells grown either in the presence or absence of a soluble calcium source promoting biomineralization. Our preliminary results exposed a role for the formation of free radicals in membrane nucleation during the process, several novel signaling cascades and potential transporters. Furthermore, these results were consistent with our scanning transmitting electron microscopy analysis that revealed the storage of calcium carbonate occurs in a controlled environment within the bacterial cells.

Calcite minerals may serve as a load-bearing foundation in complex structures, promoting the stability of the overall structure. We now study the roles of the candidate genes rising from the transcriptome in biomineralization and ask whether the compartmentalization of these gene products within the cells has an active role in mineral production. Our results will shed light on the precise role the biofilm cells have during biomineralization.