Mineralisation of an extremotolerant Bacterium Isolated from an Early Mars Analog Environment.

Introduction: Assessing the biological origin of microstructures present in rocky materials is very chal-lenging mainly due to the degradation of microbial remains during diagenesis and to mineralogical processes leading to abiotic artifacts. To better understand the processes leading to microfossil formation and preservation, artificial mineralisation of microorganisms was first undertaken with the silicification of Cyanobacteria [1], followed by the mineralisation of eukaryotic and bacterial models [2] or of natural communities [3] and has since been notably extended to hyperthermophilic Archaea [4].