Figure 1.
Schematic representation of the methodology employed to investigate the survival of F. prausnitzii in different formulations upon exposure to air.
Steps 1–4 were conducted in an anaerobic chamber, and steps 5–7 were conducted aerobically in ambient air. The final step 8, involving rehydration and viability assays, was conducted in an anaerobic chamber.
Figure 2.
Physical appearance of freeze-dried granules containing F. praunitzii.
A, Formulation with cysteine and riboflavin results in compact and pellet-like granules. B, Formulation with inulin, riboflavin and cysteine results in a foam-like matrix with a high bulk volume. C, Formulation with wheat bran, inulin, corn starch, cysteine and riboflavin results in hard and compact granules with considerable bulk volume.
Table 1.
Survival of F. prausnitzii in different formulations.
Figure 3.
Scanning electron micrographs of F. prausnitzii-containing formulations.
All formulations shown contained cysteine and riboflavin supplemented either with corn starch (A), inulin (B), or wheat bran, corn starch and inulin (C and D). Corn starch has a discrete bead-like appearence (A). In contrast, inulin forms a flake-like matrix (B), that can form a coating around corn starch and/or wheat bran, thereby entrapping the bacterial cells (C and D). Images A, B and C were recorded at 500× magnification, and image D was recorded at 1500× magnification. The arrows indicate entrapped F. prausnitzii cells.
Figure 4.
Tentative schematic representation of a formulation in which F. prausnitzii cells were adhered on cornstarch or wheat bran, and entrapped by an inulin matrix containing riboflavin and cysteine as antioxidants and redox mediators.