**5. Conclusions**

The study gave more information about the intestinal environment in vitro concerning sulfate and lactate concentrations and their e ffects on the growth parameters of *Desulfovibrio piger* Vib-7. Almost total consumption of sulfate and lactate was achieved after 60 h of cultivation, though the best relative growth and stability was measured at 7 mM and 35.6 mM of sulfate and lactate, respectively. PCA including separated parameters did not show combined clusters, but PCA based on all parameters showed that di fferent concentrations of sulfate and lactate formed separated clusters. These obtained results represent the main findings of the research, indicating that SRB would grow at the highest level under these experimentally simulated conditions. These conditions are an indicator of higher SRB activity that can lead to the development of IBD, and further studies will certainly focus more on the intestinal environment concerning SRB not only in vitro, but also in vivo.

**Author Contributions:** Conceptualization, I.K. and D.D.; methodology, I.K. and M.V.; validation, P.K., M.V., and D.D.; formal analysis, M.V. and L.D.; investigation, I.K.; resources, I.K.; data curation, D.D.; writing—original draft preparation, I.K., D.D., and M.V.; writing—review and editing, I.K. and L.D.; visualization, I.K.; supervision, M.V.; project administration, I.K.; funding acquisition, I.K., D.D., and P.K.

**Funding:** This research was supported by Grant Agency of the Masaryk University (MUNI/A/0902/2018).

**Conflicts of Interest:** The authors declare no conflict of interest.
