## 4 Discussion  
Three LAB species are by far the most dominant representatives of sourdough microbiota: _Fructilactobacillus santrancisensis_, _Lv. brevis_, and _Lp. plantarum_[40, 41]. This corresponds well with the LAB species composition of the sourdough preparations from the different types of flour in our study, where strains of _Lv. brevis_, _Lp. plantarum_ ssp. _plantarum_, and _Lp. paraplantarum_ were identified. [PERSON] and [PERSON] (2007) [49] noted that, in sourdough, _Lp. pentosus_ and _Lp. paraplantarum_ may also be present, but misidentified as _Lp. plantarum_ unless species-specific PCR targeting the _recA_ gene is performed [33]. Indeed, in our experiments, the identification of _Lp. paraplantarum_ isolates was possible only after this additional species-specific PCR analysis had been performed. In the analyzed sourdough samples, no _F. santrancisensis_ isolates were identified, but it has been shown that the presence of this species in sourdough may be closely related to the method of sourdough production [50, 51]. [PERSON] et al. (2017) [44] demonstrated that _Fr. santrancisensis_ was a characteristic species in Type I sourdough fermented \begin{table}
\begin{tabular}{c c c} \hline \hline
**Flour Type** & **Isolate** & **Identification** \\ \hline \multirow{2}{*}{Barley flour} & Ech1 & _Lactiplantitobacillus plantarum_ ssp. _plantarum_ \\  & Ech3 & _Levilactobacillus brevis_ \\ \hline \multirow{2}{*}{Spelt flour} & L1 & _Lactiplantitobacillus plantarum_ ssp. _plantarum_ \\  & L2 & _Levilactobacillus brevis_ \\ \hline \multirow{2}{*}{Buckwheat flour} & El1 & _Levilactobacillus brevis_ \\ \hline \multirow{2}{*}{Khorosan} & X2 & _Levilactobacillus brevis_ \\  & X4 & _Levilactobacillus brevis_ \\ \hline \multirow{2}{*}{Spelled flour} & Cn1 & _Lactiplantitobacillus plantarum_ ssp. _plantarum_ \\ \hline \multirow{4}{*}{ Wheat flour} & Ph1 & _Levilactobacillus brevis_ \\  & Ph2 & _Lactiplantitobacillus plantarum_ ssp. _plantarum_ \\  & Ph3 & _Lactiplantitobacillus paraplantarum_ \\  & Ph5 & _Lactiplantitobacillus parapplantarum_ \\ \hline \multirow{2}{*}{Corn flour} & Car & _Levilactobacillus brevis_ \\ \end{tabular}
\end{table} 
Table 4: Species identification of sourdough isolates of lactobacilli based on combining 165 rDNA sequence analysis and species-specific PCR. Figure 3: Species-specific PCR amplificons distinguishing the _Lactiplantitobacillus plantarum_, _Lp. pentosus_, and _Lp. paraplantarum_ species. Lanes-isolate: 1—Ech1; 2—Ph2; 3—Ph3; 4—Ph5; 5—L1; 6—Cn1; and 7—100-bp DNA ladder. at room temperature for 24 h and regularly back-slopped. Other types of sourdough have been described, type 0 being sponge dough with fast growth of baker's yeast and limited time for LAB development; type II, liquid dough with less dry matter; and type III, dried derivatives of type II sourdough [39]. The spontaneously fermented sourdoughs produced from different types of flour in this study were typical Type I sourdoughs, as they were fermented at 30 \({}^{\circ}\)C for 24 h and regularly back-slopped. According to a review by [PERSON] and [PERSON], 2019 [52], the literature data on 227 type I sourdoughs, which included mainly samples from Germany, Italy, France, Belgium, the U.S., and Canada, since 2015, demonstrated that more than 95% of sourdoughs contain heterofermatative LAB alone or in association with homoformetrative lactobacilli. _F. santranicscensis_ was most frequently identified. Other frequent representatives included _Lp. plantarum_ and _Lv. brevis_, species in the _Companilactobacillus alimentarius_ group (_C. paralimentarius_, _L. crustorum_, _L. mindensis_, and _L. nantensis_), _Leuconostc_ sp., and _Weissella_ sp. An extensive review of [PERSON] et al. (2021) [39] pointed out that \"in general less than three different LAB species inhabit a single bakery sourdough\" and the microbiota included both homo- and heterofermatative lactobacilli [44]. The results of the present study agree with both authors, with _Lv. brevis_ being the obligately heterofermatative representative and _Lp.