Extracellular Phosphate Modulation and Polyphosphate Accumulation by and .

(1) Background: An alternative and understudied microbial mechanism that may influence demineralization is the microbially mediated ion exchange of Ca and orthophosphate (P), which alters the saturation state of the mineral species within the surface enamel. There is a need to examine the ability of members of the oral microbiome to modulate Ca and P, which control mineral solubility, in order to effectively evaluate mineralization therapies to improve oral health. (2) Methods: P uptake was measured using an ascorbic acid assay during a BHI liquid culture growth of and for up to 20 h. The initial and endpoint medium Ca levels were measured using ICP-OES. Bacterial cells were examined at different growth stages using DAPI/polyP binding emission at 525 nm to detect the presence of internalized macromolecules of polyphosphates (polyP) that could drive P uptake. (3) Results: ( = 0.0061) substantially accumulated P (3.84 mmol/L), with a concomitant formation of polyP. In contrast, not take up P or accumulate polyP. No significant Ca drawdown in the media was observed in either strain. (4) Conclusions: This study suggests that when examining the future efficacy of prevention technologies to improve, in vitro assays may consider including specific oral bacteria capable of substantial P uptake.