Figure 1.
Change with time of dissolved total phosphate concentration in the sterile (dash) and inoculated (triangle) DSMZ medium after complementation with NaHCO3 (at time 0).
Table 1.
Elemental analysis of a washed sample of C. hydrogenoformans culture grown on DSMZ medium compared to biomass elemental composition from literature [51].
Table 2.
Comparison of the elemental chemical composition of whitlockite [27], hydroxyapatite [52], octacalcium [53] to the elemental composition of suspended solids obtained after 39 days of C. hydrogenoformans growth on DSMZ medium. N.D.: not determined.
Figure 2.
Black: dried precipitate formed and obtained after 30 days of C. hydrogenoformans growth in the DSMZ medium. Red: whitlockite from the JCPDS (Joint Committee on Powder Diffraction Standards) database (number 01-070-1786).
Figure 3.
XRD spectra of the dried precipitate recovered after 30 days of C. hydrogenoformans growth in the DSMZ medium (identified as ‘Dried sample’), the dried sample after having been calcinated (identified as ‘Calcinated sample’), the commercial sintered β-TCP, and the whitlockite, calculated according to the JCPDS (Joint Committee on Powder Diffraction Standards) database (number 01-070-1786).
Figure 4.
XRD pattern of the dried precipitate formed and sampled after 30 days of aging in the sterile DSMZ medium.
Figure 5.
FTIR analysis of precipitate after 30 days of aging.
Dried precipitate from sterile DSMZ medium (continuous line) and calcinated precipitate from the C. hydrogenoformans culture in the DSMZ medium (triangles).
Figure 6.
SEM-EDX analysis of two areas from a calcinated precipitate isolated after 30 days of C. hydrogenoformans growth in the DSMZ medium.
Images on the left show two levels of magnification of same area. Images on the right show EDX spectrum of two distinct areas of the sample.
Figure 7.
SEM-EDX analysis of two areas from a precipitate recovered and dried after 30 days of aging in the sterile DSMZ medium.
Images on the left show two levels of magnification of same area. Images on the right show EDX spectrum of two distinct areas of the sample.
Figure 8.
Images (A, C) and corresponding TEM-EDS analysis (B, D) of two areas in a whole-mount sample recovered after 30 days from the culture in the DSMZ medium.
(C) Magnification of the area in (A) showing biofilm covering and binding the granules, (B) Spectrum from the granule labelled B. (D) Spectrum from the organic material labelled D. (E, F) HR-TEM images of the granules' edges showing lattice fringes.
Figure 9.
TEM imaging of solids identified in sterile and inoculated DSMZ media.
(A) Sample recovered from the sterile DSMZ medium after 15 days of aging. ACP granules embedded in resin are visible. (B, C, D) Images from samples recovered after 3, 8 and 15 days respectively from a time course experiment in inoculated DSMZ medium. Three solid phases are distinct and interpreted to be either amorphous CaP (ACP) or whitlockite (W) and nanocrystalline hydroxyl-apatite (HAP). Bacteria (B) are also visible.
Figure 10.
TEM imaging of the inoculated DSMZ medium sampled after 6 days of culture.
A to D show magnification of cell lysis and spatial association of the lysed vesicle of C. hydrogenoformans and the interpreted HAP.
Figure 11.
Backscatter electron image and EDS analysis by SEM of samples recovered after 15 days, also shown in Figure 9.
(A) Sample recovered from sterile DSMZ medium, and (B) EDS analysis of its precipitate. (C) EDS analysis of the embedding epoxy matrix. (D) Sample recovered after 15 days of C. hydrogenoformans growth in the DSMZ medium, and (E) EDS analysis of its solid precipitate, (F) EDS analysis of its embedding epoxy matrix showing that Ca and P are present.