## 5 Conclusions  
In the present study, the lactobacilli in sourdough obtained from seven different types of flour were identified at the species level. The isolated cultures were affiliated with the _Lv. brevis_, _Lp. plantarum_ ssp. _plantarum_, and _Lp. paraplantarum_ species. Although the application of some flour types resulted in the isolation of common strains, nine different genotypes were identified, underlining the high strain diversity of lactobacilli in sourdough. The precise species identification of lactobacilli was only possible by combining the results of different phenotypic and molecular-genetic approaches. The next step in the research would involve the examination of the different technological properties of the studied strains, including the characterization of beneficial gene content by the whole-genome sequencing of promising cultures and the development of multi-strain sourdough starters for the preparation of bread from different flour types. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14052093/s1](https://www.mdpi.com/article/10.3390/app14052093/s1)]([https://www.mdpi.com/article/10.3390/app14052093/s1](https://www.mdpi.com/article/10.3390/app14052093/s1)): **Table S1. ** Cell morphology of the obtained isolates grown on MRS-agar. **Table S2. ** Most discriminative carbohydrate utilization patterns of the tested isolates. **Figure S1. ** Restriction profiles of 16S-ribosomal DNA of the studied isolates treated with the restriction enzyme _Hae_III. **Table S3. ** Hits from the NCBI database with \(\geq\)99% similarity to the partial 16S-rDNA sequences of the studied isolates. **Figure S2. ** Phylogenetic tree of the most common _Lactobacillus_ species found in souroughough. **Author Contributions:** Conceptualization, R.D.-K., Z.U. and Z.D. ; methodology, R.D.-K. and Z.U. ; software, Z.U. and G.K.; validation, Z.D. and Z.U. ; formal analysis, D.D., Z.U., I.P. and B.G. ; investigation, D.D., Z.U., I.P. and B.G. ; resources, Z.U. and R.D.-K.; data curation, R.D.-K.; writing--original draft preparation, R.D.-K., I.P. and A.K. ; writing--review and editing, Z.U. and Z.D. ; visualization, G.K.; supervision, A.K. and R.D.-K. All authors have read and agreed to the published version of the manuscript. **Funding:** This research received no external funding. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The data presented in this study are available in article and Supplementary Materials. **Conflicts of Interest:** Authors [PERSON] and [PERSON] were employees of LB Bulgarum Plc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. **References**  
* [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Inhibition of _Clostridium difficile_ strains by intestinal _Lactobacillus_ species. _J. Med. Microbiol._**2004**, 53, 551-554. [CrossRef]
* [PERSON] 133--Other Gram-Positive Bacilli. In _Principles and Practice of Pediatric Infectious Diseases_, 5 th ed. ; [PERSON], [PERSON], [PERSON], [PERSON]; Elsevier: Amsterdam, The Netherlands, 2018; pp. 786-790. [CrossRef]
* [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] _Lactobacillus fermentum:_ A bacterial species with potential for food preservation and biomedical applications. _Crit. Rev. Food Sci. Nutr._**2020**, 60, 3387-3399. [CrossRef]
* [PERSON]; [PERSON] Host-adapted lactobacillin in food fermentations: Impact of metabolic traits of host adapted lactobacilli on food quality and human health. _Curr. Opin. Food Sci._**2020**, 31, 71-80. [CrossRef]
* [PERSON] [PERSON]; [PERSON]; [PERSON]; [PERSON] [PERSON] _Lactobacillus heleticus_: Health effects, current applications, and future trends in dairy fermentation. _Trends Food Sci. Technol._**2023**, 136, 159-168.