Fig 1.
Map showing the landing sites for landers sent by NASA for Mars exploration.
The respective landing years are mentioned in brackets. The Mars visit which found perchlorate on the Martian surface is highlighted. Mars map adapted from NASA-JPL/Caltech.
Fig 2.
Phenol Red plate Assay for SI_IISc_isolate (also called SI) to test for ureolysis activity.
(a) Control_ No bacteria on SMU + 0.001% Phenol Red Dye. (b) SI spot inoculated on SMU + Dye. The colour change from yellow to pink represents the pH change of the media from ~5.5 to.8 and above. (c) SI spot inoculated on SMU + Dye + 25mM CaCl2. The white lines on the plate represent calcite precipitate. Note: Plate dimensions- 90x14mm.
Fig 3.
(a) Scanning Electron Microscopy images of the calcite precipitate made by the MICP-capable bacteria SI via its ureolytic activity. (b) X-Ray Diffraction (XRD) results for the precipitate. C represents Calcite, V represents Vaterite, A for aragonite, and peaks as identified through the ICSD database sub-file.
Fig 4.
Maximum Likelihood tree of 16S rRNA showing the relationship of SI_IISc isolate with closely related taxa, values in node indicate bootstrap support.
Inset is a SEM image of the SI_IISc isolate.
Fig 5.
Genome map showing a circular map of the genome (representation only), identified genes, GC Content, and GC Skew of SI_IISc isolate.
Fig 6.
Gram-staining results showing the difference in cell morphology and behaviour of the Sporosarcina sp. strain SI_IISc _isolate(or SI).
(a) SI Control (b) SI + 0.5%Perchlorate (c) SI + 1%Perchlorate (d) SI + 2%Perchlorate. The lower panel represents magnified portions of corresponding images in the top panel. The scale bar represents 10µm.
Fig 7.
Scanning Electron Microscopy: Images of the total precipitate formed from bacterial exposure to different concentrations of perchlorate (as (MgClO4)2).
(a) to (c) SEM images for total precipitate with SI + 0.5%Perchlorate (d) to (f) with SI + 1%Perchlorate & (g) to (i) for SI + 2%Perchlorate. The scale bar represents 5 µm.
Fig 8.
Schematic depicting the brick casting procedure alongside the consolidation process facilitated by MICP in simulated regolith.
Fig 9.
Panel (a) illustrates the stress-strain behaviour of the bio-consolidated specimen subjected to compressive loading.
The peak stress observed was designated as the compressive strength of the consolidated brick. The inset provides a visual representation of the Martian brick specimen ‘s (made with Martian regolith+ SI + G + N + P) condition during loading, displaying the initial state of the specimen on the left and its final state on the right, with arrows indicating the locations of cracks. Panel (b) presents the compressive strength
, averaged from a minimum of four specimens across various treatment conditions. Error bars indicate the variability in brick strength. The treatments DI and DI + G were treated as a control to check for the significance of MICP and compared with SI and SI + G, respectively. The treatments examined include SI, SI + G, and SI + G + N, serving as controls to assess the influence of perchlorate on the compressive strength of the bricks, a control to check for the significance of MICP and compared with SI and SI + G, respectively. The treatments examined include SI, SI + G, and SI + G + N, serving as controls(i.e., without perchlorate) to assess the influence of perchlorate on the compressive strength of the bricks, a measure indicative of MICP mediation.